Merge branch 'taesd-preview' of https://github.com/space-nuko/ComfyUI

README.md

@@ -29,6 +29,7 @@ This ui will let you design and execute advanced stable diffusion pipelines usin
 - [Upscale Models (ESRGAN, ESRGAN variants, SwinIR, Swin2SR, etc...)](https://comfyanonymous.github.io/ComfyUI_examples/upscale_models/)
 - [unCLIP Models](https://comfyanonymous.github.io/ComfyUI_examples/unclip/)
 - [GLIGEN](https://comfyanonymous.github.io/ComfyUI_examples/gligen/)
+- Latent previews with [TAESD](https://github.com/madebyollin/taesd)
 - Starts up very fast.
 - Works fully offline: will never download anything.
 - [Config file](extra_model_paths.yaml.example) to set the search paths for models.
@@ -181,6 +182,10 @@ You can set this command line setting to disable the upcasting to fp32 in some c
 
 ```--dont-upcast-attention```
 
+## How to show high-quality previews?
+
+The default installation includes a fast latent preview method that's low-resolution. To enable higher-quality previews with [TAESD](https://github.com/madebyollin/taesd), download the [taesd_encoder.pth](https://github.com/madebyollin/taesd/raw/main/taesd_encoder.pth) and [taesd_decoder.pth](https://github.com/madebyollin/taesd/raw/main/taesd_decoder.pth) models and place them in the `models/taesd` folder. Once they're installed, restart ComfyUI to enable high-quality previews.
+
 ## Support and dev channel
 
 [Matrix space: #comfyui_space:matrix.org](https://app.element.io/#/room/%23comfyui_space%3Amatrix.org) (it's like discord but open source).

comfy/cli_args.py

@@ -1,4 +1,35 @@
 import argparse
+import enum
+
+
+class EnumAction(argparse.Action):
+    """
+    Argparse action for handling Enums
+    """
+    def __init__(self, **kwargs):
+        # Pop off the type value
+        enum_type = kwargs.pop("type", None)
+
+        # Ensure an Enum subclass is provided
+        if enum_type is None:
+            raise ValueError("type must be assigned an Enum when using EnumAction")
+        if not issubclass(enum_type, enum.Enum):
+            raise TypeError("type must be an Enum when using EnumAction")
+
+        # Generate choices from the Enum
+        choices = tuple(e.value for e in enum_type)
+        kwargs.setdefault("choices", choices)
+        kwargs.setdefault("metavar", f"[{','.join(list(choices))}]")
+
+        super(EnumAction, self).__init__(**kwargs)
+
+        self._enum = enum_type
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        # Convert value back into an Enum
+        value = self._enum(values)
+        setattr(namespace, self.dest, value)
+
 
 parser = argparse.ArgumentParser()
 
@@ -13,6 +44,13 @@ parser.add_argument("--dont-upcast-attention", action="store_true", help="Disabl
 parser.add_argument("--force-fp32", action="store_true", help="Force fp32 (If this makes your GPU work better please report it).")
 parser.add_argument("--directml", type=int, nargs="?", metavar="DIRECTML_DEVICE", const=-1, help="Use torch-directml.")
 
+class LatentPreviewMethod(enum.Enum):
+    Auto = "auto"
+    Latent2RGB = "latent2rgb"
+    TAESD = "taesd"
+parser.add_argument("--disable-previews", action="store_true", help="Disable showing node previews.")
+parser.add_argument("--default-preview-method", type=str, default=LatentPreviewMethod.Auto, metavar="PREVIEW_METHOD", help="Default preview method for sampler nodes.")
+
 attn_group = parser.add_mutually_exclusive_group()
 attn_group.add_argument("--use-split-cross-attention", action="store_true", help="Use the split cross attention optimization instead of the sub-quadratic one. Ignored when xformers is used.")
 attn_group.add_argument("--use-pytorch-cross-attention", action="store_true", help="Use the new pytorch 2.0 cross attention function.")

comfy/taesd/taesd.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""
+Tiny AutoEncoder for Stable Diffusion
+(DNN for encoding / decoding SD's latent space)
+"""
+import torch
+import torch.nn as nn
+
+def conv(n_in, n_out, **kwargs):
+    return nn.Conv2d(n_in, n_out, 3, padding=1, **kwargs)
+
+class Clamp(nn.Module):
+    def forward(self, x):
+        return torch.tanh(x / 3) * 3
+
+class Block(nn.Module):
+    def __init__(self, n_in, n_out):
+        super().__init__()
+        self.conv = nn.Sequential(conv(n_in, n_out), nn.ReLU(), conv(n_out, n_out), nn.ReLU(), conv(n_out, n_out))
+        self.skip = nn.Conv2d(n_in, n_out, 1, bias=False) if n_in != n_out else nn.Identity()
+        self.fuse = nn.ReLU()
+    def forward(self, x):
+        return self.fuse(self.conv(x) + self.skip(x))
+
+def Encoder():
+    return nn.Sequential(
+        conv(3, 64), Block(64, 64),
+        conv(64, 64, stride=2, bias=False), Block(64, 64), Block(64, 64), Block(64, 64),
+        conv(64, 64, stride=2, bias=False), Block(64, 64), Block(64, 64), Block(64, 64),
+        conv(64, 64, stride=2, bias=False), Block(64, 64), Block(64, 64), Block(64, 64),
+        conv(64, 4),
+    )
+
+def Decoder():
+    return nn.Sequential(
+        Clamp(), conv(4, 64), nn.ReLU(),
+        Block(64, 64), Block(64, 64), Block(64, 64), nn.Upsample(scale_factor=2), conv(64, 64, bias=False),
+        Block(64, 64), Block(64, 64), Block(64, 64), nn.Upsample(scale_factor=2), conv(64, 64, bias=False),
+        Block(64, 64), Block(64, 64), Block(64, 64), nn.Upsample(scale_factor=2), conv(64, 64, bias=False),
+        Block(64, 64), conv(64, 3),
+    )
+
+class TAESD(nn.Module):
+    latent_magnitude = 3
+    latent_shift = 0.5
+
+    def __init__(self, encoder_path="taesd_encoder.pth", decoder_path="taesd_decoder.pth"):
+        """Initialize pretrained TAESD on the given device from the given checkpoints."""
+        super().__init__()
+        self.encoder = Encoder()
+        self.decoder = Decoder()
+        if encoder_path is not None:
+            self.encoder.load_state_dict(torch.load(encoder_path, map_location="cpu"))
+        if decoder_path is not None:
+            self.decoder.load_state_dict(torch.load(decoder_path, map_location="cpu"))
+
+    @staticmethod
+    def scale_latents(x):
+        """raw latents -> [0, 1]"""
+        return x.div(2 * TAESD.latent_magnitude).add(TAESD.latent_shift).clamp(0, 1)
+
+    @staticmethod
+    def unscale_latents(x):
+        """[0, 1] -> raw latents"""
+        return x.sub(TAESD.latent_shift).mul(2 * TAESD.latent_magnitude)

comfy/utils.py

@@ -1,6 +1,7 @@
 import torch
 import math
 import struct
+import comfy.model_management
 
 def load_torch_file(ckpt, safe_load=False):
     if ckpt.lower().endswith(".safetensors"):
@@ -166,6 +167,8 @@ def tiled_scale(samples, function, tile_x=64, tile_y=64, overlap = 8, upscale_am
         out_div = torch.zeros((s.shape[0], out_channels, round(s.shape[2] * upscale_amount), round(s.shape[3] * upscale_amount)), device="cpu")
         for y in range(0, s.shape[2], tile_y - overlap):
             for x in range(0, s.shape[3], tile_x - overlap):
+                comfy.model_management.throw_exception_if_processing_interrupted()
+
                 s_in = s[:,:,y:y+tile_y,x:x+tile_x]
 
                 ps = function(s_in).cpu()
@@ -197,14 +200,14 @@ class ProgressBar:
         self.current = 0
         self.hook = PROGRESS_BAR_HOOK
 
-    def update_absolute(self, value, total=None):
+    def update_absolute(self, value, total=None, preview=None):
         if total is not None:
             self.total = total
         if value > self.total:
             value = self.total
         self.current = value
         if self.hook is not None:
-            self.hook(self.current, self.total)
+            self.hook(self.current, self.total, preview)
 
     def update(self, value):
         self.update_absolute(self.current + value)

folder_paths.py

@@ -18,6 +18,7 @@ folder_names_and_paths["clip_vision"] = ([os.path.join(models_dir, "clip_vision"
 folder_names_and_paths["style_models"] = ([os.path.join(models_dir, "style_models")], supported_pt_extensions)
 folder_names_and_paths["embeddings"] = ([os.path.join(models_dir, "embeddings")], supported_pt_extensions)
 folder_names_and_paths["diffusers"] = ([os.path.join(models_dir, "diffusers")], ["folder"])
+folder_names_and_paths["taesd"] = ([os.path.join(models_dir, "taesd")], supported_pt_extensions)
 
 folder_names_and_paths["controlnet"] = ([os.path.join(models_dir, "controlnet"), os.path.join(models_dir, "t2i_adapter")], supported_pt_extensions)
 folder_names_and_paths["gligen"] = ([os.path.join(models_dir, "gligen")], supported_pt_extensions)

main.py

@@ -26,6 +26,7 @@ import yaml
 import execution
 import folder_paths
 import server
+from server import BinaryEventTypes
 from nodes import init_custom_nodes
 
 
@@ -40,8 +41,10 @@ async def run(server, address='', port=8188, verbose=True, call_on_start=None):
     await asyncio.gather(server.start(address, port, verbose, call_on_start), server.publish_loop())
 
 def hijack_progress(server):
-    def hook(value, total):
+    def hook(value, total, preview_image_bytes):
         server.send_sync("progress", { "value": value, "max": total}, server.client_id)
+        if preview_image_bytes is not None:
+            server.send_sync(BinaryEventTypes.PREVIEW_IMAGE, preview_image_bytes, server.client_id)
     comfy.utils.set_progress_bar_global_hook(hook)
 
 def cleanup_temp():

nodes.py

@@ -7,6 +7,8 @@ import hashlib
 import traceback
 import math
 import time
+import struct
+from io import BytesIO
 
 from PIL import Image, ImageOps
 from PIL.PngImagePlugin import PngInfo
@@ -22,6 +24,8 @@ import comfy.samplers
 import comfy.sample
 import comfy.sd
 import comfy.utils
+from comfy.cli_args import args, LatentPreviewMethod
+from comfy.taesd.taesd import TAESD
 
 import comfy.clip_vision
 
@@ -31,6 +35,32 @@ import importlib
 import folder_paths
 
 
+class LatentPreviewer:
+    def decode_latent_to_preview(self, device, x0):
+        pass
+
+
+class Latent2RGBPreviewer(LatentPreviewer):
+    def __init__(self):
+        self.latent_rgb_factors = torch.tensor([
+                    #   R        G        B
+                    [0.298, 0.207, 0.208],  # L1
+                    [0.187, 0.286, 0.173],  # L2
+                    [-0.158, 0.189, 0.264],  # L3
+                    [-0.184, -0.271, -0.473],  # L4
+                ], device="cpu")
+
+    def decode_latent_to_preview(self, device, x0):
+        latent_image = x0[0].permute(1, 2, 0).cpu() @ self.latent_rgb_factors
+
+        latents_ubyte = (((latent_image + 1) / 2)
+                            .clamp(0, 1)  # change scale from -1..1 to 0..1
+                            .mul(0xFF)  # to 0..255
+                            .byte()).cpu()
+
+        return Image.fromarray(latents_ubyte.numpy())
+
+
 def before_node_execution():
     comfy.model_management.throw_exception_if_processing_interrupted()
 
@@ -38,6 +68,7 @@ def interrupt_processing(value=True):
     comfy.model_management.interrupt_current_processing(value)
 
 MAX_RESOLUTION=8192
+MAX_PREVIEW_RESOLUTION = 512
 
 class CLIPTextEncode:
     @classmethod
@@ -248,6 +279,21 @@ class VAEEncodeForInpaint:
 
         return ({"samples":t, "noise_mask": (mask_erosion[:,:,:x,:y].round())}, )
 
+class TAESDPreviewerImpl(LatentPreviewer):
+    def __init__(self, taesd):
+        self.taesd = taesd
+
+    def decode_latent_to_preview(self, device, x0):
+        x_sample = self.taesd.decoder(x0.to(device))[0].detach()
+        # x_sample = self.taesd.unscale_latents(x_sample).div(4).add(0.5)  # returns value in [-2, 2]
+        x_sample = x_sample.sub(0.5).mul(2)
+
+        x_sample = torch.clamp((x_sample + 1.0) / 2.0, min=0.0, max=1.0)
+        x_sample = 255. * np.moveaxis(x_sample.cpu().numpy(), 0, 2)
+        x_sample = x_sample.astype(np.uint8)
+
+        preview_image = Image.fromarray(x_sample)
+        return preview_image
 
 class SaveLatent:
     def __init__(self):
@@ -931,6 +977,26 @@ class SetLatentNoiseMask:
         s["noise_mask"] = mask.reshape((-1, 1, mask.shape[-2], mask.shape[-1]))
         return (s,)
 
+
+def decode_latent_to_preview_image(previewer, device, preview_format, x0):
+    preview_image = previewer.decode_latent_to_preview(device, x0)
+    preview_image = ImageOps.contain(preview_image, (MAX_PREVIEW_RESOLUTION, MAX_PREVIEW_RESOLUTION), Image.ANTIALIAS)
+
+    preview_type = 1
+    if preview_format == "JPEG":
+        preview_type = 1
+    elif preview_format == "PNG":
+        preview_type = 2
+
+    bytesIO = BytesIO()
+    header = struct.pack(">I", preview_type)
+    bytesIO.write(header)
+    preview_image.save(bytesIO, format=preview_format)
+    preview_bytes = bytesIO.getvalue()
+
+    return preview_bytes
+
+
 def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent, denoise=1.0, disable_noise=False, start_step=None, last_step=None, force_full_denoise=False):
     device = comfy.model_management.get_torch_device()
     latent_image = latent["samples"]
@@ -945,9 +1011,39 @@ def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive,
     if "noise_mask" in latent:
         noise_mask = latent["noise_mask"]
 
+    preview_format = "JPEG"
+    if preview_format not in ["JPEG", "PNG"]:
+        preview_format = "JPEG"
+
+    previewer = None
+    if not args.disable_previews:
+        # TODO previewer methods
+        taesd_encoder_path = folder_paths.get_full_path("taesd", "taesd_encoder.pth")
+        taesd_decoder_path = folder_paths.get_full_path("taesd", "taesd_decoder.pth")
+
+        method = args.default_preview_method
+
+        if method == LatentPreviewMethod.Auto:
+            method = LatentPreviewMethod.Latent2RGB
+            if taesd_encoder_path and taesd_encoder_path:
+                method = LatentPreviewMethod.TAESD
+
+        if method == LatentPreviewMethod.TAESD:
+            if taesd_encoder_path and taesd_encoder_path:
+                taesd = TAESD(taesd_encoder_path, taesd_decoder_path).to(device)
+                previewer = TAESDPreviewerImpl(taesd)
+            else:
+                print("Warning: TAESD previews enabled, but could not find models/taesd/taesd_encoder.pth and models/taesd/taesd_decoder.pth")
+
+        if previewer is None:
+            previewer = Latent2RGBPreviewer()
+
     pbar = comfy.utils.ProgressBar(steps)
     def callback(step, x0, x, total_steps):
-        pbar.update_absolute(step + 1, total_steps)
+        preview_bytes = None
+        if previewer:
+            preview_bytes = decode_latent_to_preview_image(previewer, device, preview_format, x0)
+        pbar.update_absolute(step + 1, total_steps, preview_bytes)
 
     samples = comfy.sample.sample(model, noise, steps, cfg, sampler_name, scheduler, positive, negative, latent_image,
                                   denoise=denoise, disable_noise=disable_noise, start_step=start_step, last_step=last_step,
@@ -970,7 +1066,8 @@ class KSampler:
                     "negative": ("CONDITIONING", ),
                     "latent_image": ("LATENT", ),
                     "denoise": ("FLOAT", {"default": 1.0, "min": 0.0, "max": 1.0, "step": 0.01}),
-                    }}
+                     }
+                }
 
     RETURN_TYPES = ("LATENT",)
     FUNCTION = "sample"
@@ -997,7 +1094,8 @@ class KSamplerAdvanced:
                     "start_at_step": ("INT", {"default": 0, "min": 0, "max": 10000}),
                     "end_at_step": ("INT", {"default": 10000, "min": 0, "max": 10000}),
                     "return_with_leftover_noise": (["disable", "enable"], ),
-                    }}
+                     }
+                }
 
     RETURN_TYPES = ("LATENT",)
     FUNCTION = "sample"

server.py

@@ -7,6 +7,7 @@ import execution
 import uuid
 import json
 import glob
+import struct
 from PIL import Image
 from io import BytesIO
 
@@ -25,6 +26,11 @@ from comfy.cli_args import args
 import comfy.utils
 import comfy.model_management
 
+
+class BinaryEventTypes:
+    PREVIEW_IMAGE = 1
+
+
 @web.middleware
 async def cache_control(request: web.Request, handler):
     response: web.Response = await handler(request)
@@ -457,16 +463,37 @@ class PromptServer():
         return prompt_info
 
     async def send(self, event, data, sid=None):
-        message = {"type": event, "data": data}
+        if isinstance(data, (bytes, bytearray)):
+            await self.send_bytes(event, data, sid)
+        else:
+            await self.send_json(event, data, sid)
+
+    def encode_bytes(self, event, data):
+        if not isinstance(event, int):
+            raise RuntimeError(f"Binary event types must be integers, got {event}")
+
+        packed = struct.pack(">I", event)
+        message = bytearray(packed)
+        message.extend(data)
+        return message
 
-        if isinstance(message, str) == False:
-            message = json.dumps(message)
+    async def send_bytes(self, event, data, sid=None):
+        message = self.encode_bytes(event, data)
+
+        if sid is None:
+            for ws in self.sockets.values():
+                await ws.send_bytes(message)
+        elif sid in self.sockets:
+            await self.sockets[sid].send_bytes(message)
+
+    async def send_json(self, event, data, sid=None):
+        message = {"type": event, "data": data}
 
         if sid is None:
             for ws in self.sockets.values():
-                await ws.send_str(message)
+                await ws.send_json(message)
         elif sid in self.sockets:
-            await self.sockets[sid].send_str(message)
+            await self.sockets[sid].send_json(message)
 
     def send_sync(self, event, data, sid=None):
         self.loop.call_soon_threadsafe(

web/extensions/core/colorPalette.js

@@ -21,6 +21,7 @@ const colorPalettes = {
 				"MODEL": "#B39DDB", // light lavender-purple
 				"STYLE_MODEL": "#C2FFAE", // light green-yellow
 				"VAE": "#FF6E6E", // bright red
+				"TAESD": "#DCC274", // cheesecake
 			},
 			"litegraph_base": {
 				"NODE_TITLE_COLOR": "#999",

web/scripts/api.js

@@ -42,6 +42,7 @@ class ComfyApi extends EventTarget {
 		this.socket = new WebSocket(
 			`ws${window.location.protocol === "https:" ? "s" : ""}://${location.host}/ws${existingSession}`
 		);
+		this.socket.binaryType = "arraybuffer";
 
 		this.socket.addEventListener("open", () => {
 			opened = true;
@@ -70,39 +71,65 @@ class ComfyApi extends EventTarget {
 
 		this.socket.addEventListener("message", (event) => {
 			try {
-				const msg = JSON.parse(event.data);
-				switch (msg.type) {
-					case "status":
-						if (msg.data.sid) {
-							this.clientId = msg.data.sid;
-							window.name = this.clientId;
+				if (event.data instanceof ArrayBuffer) {
+					const view = new DataView(event.data);
+					const eventType = view.getUint32(0);
+					const buffer = event.data.slice(4);
+					switch (eventType) {
+					case 1:
+						const view2 = new DataView(event.data);
+						const imageType = view2.getUint32(0)
+						let imageMime
+						switch (imageType) {
+							case 1:
+							default:
+								imageMime = "image/jpeg";
+								break;
+							case 2:
+								imageMime = "image/png"
 						}
-						this.dispatchEvent(new CustomEvent("status", { detail: msg.data.status }));
-						break;
-					case "progress":
-						this.dispatchEvent(new CustomEvent("progress", { detail: msg.data }));
-						break;
-					case "executing":
-						this.dispatchEvent(new CustomEvent("executing", { detail: msg.data.node }));
-						break;
-					case "executed":
-						this.dispatchEvent(new CustomEvent("executed", { detail: msg.data }));
-						break;
-					case "execution_start":
-						this.dispatchEvent(new CustomEvent("execution_start", { detail: msg.data }));
-						break;
-					case "execution_error":
-						this.dispatchEvent(new CustomEvent("execution_error", { detail: msg.data }));
+						const imageBlob = new Blob([buffer.slice(4)], { type: imageMime });
+						this.dispatchEvent(new CustomEvent("b_preview", { detail: imageBlob }));
 						break;
 					default:
-						if (this.#registered.has(msg.type)) {
-							this.dispatchEvent(new CustomEvent(msg.type, { detail: msg.data }));
-						} else {
-							throw new Error("Unknown message type");
-						}
+						throw new Error(`Unknown binary websocket message of type ${eventType}`);
+					}
+				}
+				else {
+				    const msg = JSON.parse(event.data);
+				    switch (msg.type) {
+					    case "status":
+						    if (msg.data.sid) {
+							    this.clientId = msg.data.sid;
+							    window.name = this.clientId;
+						    }
+						    this.dispatchEvent(new CustomEvent("status", { detail: msg.data.status }));
+						    break;
+					    case "progress":
+						    this.dispatchEvent(new CustomEvent("progress", { detail: msg.data }));
+						    break;
+					    case "executing":
+						    this.dispatchEvent(new CustomEvent("executing", { detail: msg.data.node }));
+						    break;
+					    case "executed":
+						    this.dispatchEvent(new CustomEvent("executed", { detail: msg.data }));
+						    break;
+					    case "execution_start":
+						    this.dispatchEvent(new CustomEvent("execution_start", { detail: msg.data }));
+						    break;
+					    case "execution_error":
+						    this.dispatchEvent(new CustomEvent("execution_error", { detail: msg.data }));
+						    break;
+					    default:
+						    if (this.#registered.has(msg.type)) {
+							    this.dispatchEvent(new CustomEvent(msg.type, { detail: msg.data }));
+						    } else {
+							    throw new Error(`Unknown message type ${msg.type}`);
+						    }
+				    }
 				}
 			} catch (error) {
-				console.warn("Unhandled message:", event.data);
+				console.warn("Unhandled message:", event.data, error);
 			}
 		});
 	}

web/scripts/app.js

@@ -44,6 +44,12 @@ export class ComfyApp {
 		 */
 		this.nodeOutputs = {};
 
+		/**
+		 * Stores the preview image data for each node
+		 * @type {Record<string, Image>}
+		 */
+		this.nodePreviewImages = {};
+
 		/**
 		 * If the shift key on the keyboard is pressed
 		 * @type {boolean}
@@ -367,29 +373,52 @@ export class ComfyApp {
 
 		node.prototype.onDrawBackground = function (ctx) {
 			if (!this.flags.collapsed) {
+				let imgURLs = []
+				let imagesChanged = false
+
 				const output = app.nodeOutputs[this.id + ""];
 				if (output && output.images) {
 					if (this.images !== output.images) {
 						this.images = output.images;
-						this.imgs = null;
-						this.imageIndex = null;
+						imagesChanged = true;
+						imgURLs = imgURLs.concat(output.images.map(params => {
+							return "/view?" + new URLSearchParams(params).toString() + app.getPreviewFormatParam();
+						}))
+					}
+				}
+
+				const preview = app.nodePreviewImages[this.id + ""]
+				if (this.preview !== preview) {
+					this.preview = preview
+					imagesChanged = true;
+					if (preview != null) {
+						imgURLs.push(preview);
+					}
+				}
+
+				if (imagesChanged) {
+					this.imageIndex = null;
+					if (imgURLs.length > 0) {
 						Promise.all(
-							output.images.map((src) => {
+							imgURLs.map((src) => {
 								return new Promise((r) => {
 									const img = new Image();
 									img.onload = () => r(img);
 									img.onerror = () => r(null);
-									img.src = "/view?" + new URLSearchParams(src).toString() + app.getPreviewFormatParam();
+									img.src = src
 								});
 							})
 						).then((imgs) => {
-							if (this.images === output.images) {
+							if ((!output || this.images === output.images) && (!preview || this.preview === preview)) {
 								this.imgs = imgs.filter(Boolean);
 								this.setSizeForImage?.();
 								app.graph.setDirtyCanvas(true);
 							}
 						});
 					}
+					else {
+						this.imgs = null;
+					}
 				}
 
 				if (this.imgs && this.imgs.length) {
@@ -901,17 +930,20 @@ export class ComfyApp {
 			this.progress = null;
 			this.runningNodeId = detail;
 			this.graph.setDirtyCanvas(true, false);
+			delete this.nodePreviewImages[this.runningNodeId]
 		});
 
 		api.addEventListener("executed", ({ detail }) => {
 			this.nodeOutputs[detail.node] = detail.output;
 			const node = this.graph.getNodeById(detail.node);
-			if (node?.onExecuted) {
-				node.onExecuted(detail.output);
+			if (node) {
+				if (node.onExecuted)
+					node.onExecuted(detail.output);
 			}
 		});
 
 		api.addEventListener("execution_start", ({ detail }) => {
+			this.runningNodeId = null;
 			this.lastExecutionError = null
 		});
 
@@ -922,6 +954,16 @@ export class ComfyApp {
 			this.canvas.draw(true, true);
 		});
 
+		api.addEventListener("b_preview", ({ detail }) => {
+			const id = this.runningNodeId
+			if (id == null)
+				return;
+
+			const blob = detail
+			const blobUrl = URL.createObjectURL(blob)
+			this.nodePreviewImages[id] = [blobUrl]
+		});
+
 		api.init();
 	}
 
@@ -1465,8 +1507,10 @@ export class ComfyApp {
 	 */
 	clean() {
 		this.nodeOutputs = {};
+		this.nodePreviewImages = {}
 		this.lastPromptError = null;
 		this.lastExecutionError = null;
+		this.runningNodeId = null;
 	}
 }