diff --git a/package.json b/package.json
index dda1c0a..53e65a9 100644
--- a/package.json
+++ b/package.json
@@ -59,6 +59,7 @@
     "events": "^3.3.0",
     "framework7": "^8.0.3",
     "framework7-svelte": "^8.0.3",
+    "img-comparison-slider": "^8.0.0",
     "pollen-css": "^4.6.2",
     "radix-icons-svelte": "^1.2.1",
     "svelte-preprocess": "^5.0.3",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 90abd9f..a1b4366 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -79,6 +79,9 @@ importers:
       framework7-svelte:
         specifier: ^8.0.3
         version: 8.0.3
+      img-comparison-slider:
+        specifier: ^8.0.0
+        version: 8.0.0
       pollen-css:
         specifier: ^4.6.2
         version: 4.6.2
@@ -4189,6 +4192,10 @@ packages:
     engines: {node: '>= 4'}
     dev: true
 
+  /img-comparison-slider@8.0.0:
+    resolution: {integrity: sha512-ZOKkdN/+W/U/2LFEwrZuxRVbIwQK1GyEKhTETfsy55/bmBoNfM81MnQsc1j81Q50dkwTKjuecicsnp3O7lBRqQ==}
+    dev: false
+
   /immutable@4.3.0:
     resolution: {integrity: sha512-0AOCmOip+xgJwEVTQj1EfiDDOkPmuyllDuTuEX+DDXUgapLAsBIfkg3sxCYyCEA8mQqZrrxPUGjcOQ2JS3WLkg==}
 
diff --git a/src/lib/api.ts b/src/lib/api.ts
index 159d455..fa7fb35 100644
--- a/src/lib/api.ts
+++ b/src/lib/api.ts
@@ -119,6 +119,12 @@ export default class ComfyAPI extends EventTarget {
                     case "executed":
                         this.dispatchEvent(new CustomEvent("executed", { detail: msg.data }));
                         break;
+                    case "execution_cached":
+                        this.dispatchEvent(new CustomEvent("execution_cached", { 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 }));
diff --git a/src/lib/components/ComfyApp.ts b/src/lib/components/ComfyApp.ts
index 93b8673..7d309d5 100644
--- a/src/lib/components/ComfyApp.ts
+++ b/src/lib/components/ComfyApp.ts
@@ -352,6 +352,15 @@ export default class ComfyApp {
             }
         });
 
+        this.api.addEventListener("execution_cached", ({ detail }: CustomEvent) => {
+            // TODO detail.nodes
+        });
+
+        this.api.addEventListener("execution_error", ({ detail }: CustomEvent) => {
+            queueState.update(s => { s.progress = null; s.runningNodeId = null; return s; })
+            notify(`Execution error: ${detail.message}`, { type: "error", timeout: 10000 })
+        });
+
         this.api.init();
     }
 
@@ -447,6 +456,11 @@ export default class ComfyApp {
             state = structuredClone(blankGraph)
         }
         await this.deserialize(state)
+        uiState.update(s => {
+            s.uiUnlocked = true;
+            s.uiEditMode = "widgets";
+            return s;
+        })
     }
 
     /**
diff --git a/src/lib/components/ImageComparison.svelte b/src/lib/components/ImageComparison.svelte
new file mode 100644
index 0000000..8124a91
--- /dev/null
+++ b/src/lib/components/ImageComparison.svelte
@@ -0,0 +1,32 @@
+<script lang="ts">
+ import 'img-comparison-slider';
+
+ export let value: number = 50;
+ export let hover: boolean = false;
+ export let direction: "horizontal" | "vertical" = "horizontal";
+ export let nonce: string | null = null;
+ export let keyboard: "enabled" | "disabled" = "enabled";
+ export let handle: boolean = false;
+</script>
+
+<img-comparison-slider {value} {hover} {direction} {nonce} {keyboard} {handle} {...$$restProps}>
+    <slot/>
+</img-comparison-slider>
+
+<style>
+ img-comparison-slider {
+     visibility: hidden;
+ }
+
+ img-comparison-slider [slot='second'] {
+     display: none;
+ }
+
+ img-comparison-slider.rendered {
+     visibility: inherit;
+ }
+
+ img-comparison-slider.rendered [slot='second'] {
+     display: unset;
+ }
+</style>
diff --git a/src/lib/nodes/ComfyWidgetNodes.ts b/src/lib/nodes/ComfyWidgetNodes.ts
index d7dea9d..b64928e 100644
--- a/src/lib/nodes/ComfyWidgetNodes.ts
+++ b/src/lib/nodes/ComfyWidgetNodes.ts
@@ -17,6 +17,7 @@ import ButtonWidget from "$lib/widgets/ButtonWidget.svelte";
 import CheckboxWidget from "$lib/widgets/CheckboxWidget.svelte";
 import RadioWidget from "$lib/widgets/RadioWidget.svelte";
 import ImageUploadWidget from "$lib/widgets/ImageUploadWidget.svelte";
+import ImageCompareWidget from "$lib/widgets/ImageCompareWidget.svelte";
 
 export type AutoConfigOptions = {
     includeProperties?: Set<string> | null,
@@ -963,3 +964,92 @@ LiteGraph.registerNodeType({
     desc: "Widget that lets you upload images into ComfyUI's input folder",
     type: "ui/image_upload"
 })
+
+export interface ComfyImageCompareNodeProperties extends ComfyWidgetProperties {
+}
+
+export type FileNameOrGalleryData = string | GalleryOutputEntry;
+export type ImageCompareData = [FileNameOrGalleryData, FileNameOrGalleryData]
+
+export class ComfyImageCompareNode extends ComfyWidgetNode<ImageCompareData> {
+    override properties: ComfyImageCompareNodeProperties = {
+        defaultValue: [],
+        tags: [],
+    }
+
+    static slotLayout: SlotLayout = {
+        inputs: [
+            { name: "store", type: BuiltInSlotType.ACTION },
+            { name: "left_image", type: "string" },
+            { name: "right_image", type: "string" },
+        ],
+        outputs: [
+        ]
+    }
+
+    override svelteComponentType = ImageCompareWidget;
+    override defaultValue: ImageCompareData = ["", ""];
+    override outputIndex = null;
+    override changedIndex = 3;
+    override storeActionName = "store";
+    override saveUserState = false;
+
+    constructor(name?: string) {
+        super(name, ["", ""])
+    }
+
+    override onExecute() {
+        const valueA = this.getInputData(1)
+        const valueB = this.getInputData(2)
+        let current = get(this.value)
+        let changed = false;
+        if (valueA != null && current[0] != valueA) {
+            current[0] = valueA
+            changed = true;
+        }
+        if (valueB != null && current[1] != valueB) {
+            current[1] = valueB
+            changed = true;
+        }
+        if (changed)
+            this.value.set(current)
+    }
+
+    override parseValue(value: any): ImageCompareData {
+        if (value == null) {
+            return ["", ""]
+        }
+        else if (typeof value === "string" && value !== "") { // Single filename
+            const prevValue = get(this.value)
+            prevValue.push(value)
+            if (prevValue.length > 2)
+                prevValue.splice(0, 1)
+            return prevValue as ImageCompareData
+        }
+        else if (typeof value === "object" && "images" in value && value.images.length > 0) {
+            const output = value as GalleryOutput
+            const prevValue = get(this.value)
+            prevValue.push(output.images[0].filename)
+            if (prevValue.length > 2)
+                prevValue.splice(0, 1)
+            return prevValue as ImageCompareData
+        }
+        else if (Array.isArray(value) && typeof value[0] === "string" && typeof value[1] === "string") {
+            return value as ImageCompareData
+        }
+        else {
+            return ["", ""]
+        }
+    }
+
+    override formatValue(value: GradioFileData[]): string {
+        return `Images: ${value?.length || 0}`
+    }
+}
+
+LiteGraph.registerNodeType({
+    class: ComfyImageCompareNode,
+    title: "UI.ImageCompare",
+    desc: "Widget that lets you compare two images",
+    type: "ui/image_compare"
+})
diff --git a/src/lib/utils.ts b/src/lib/utils.ts
index 335a305..62e72a0 100644
--- a/src/lib/utils.ts
+++ b/src/lib/utils.ts
@@ -123,7 +123,6 @@ export const debounce = (callback: Function, wait = 250) => {
 
 export function convertComfyOutputToGradio(output: GalleryOutput): GradioFileData[] {
     return output.images.map(r => {
-        // TODO configure backend URL
         const url = `http://${location.hostname}:8188` // TODO make configurable
         const params = new URLSearchParams(r)
         const fileData: GradioFileData = {
@@ -136,6 +135,18 @@ export function convertComfyOutputToGradio(output: GalleryOutput): GradioFileDat
     });
 }
 
+export function convertFilenameToComfyURL(filename: string,
+    subfolder: string = "",
+    type: "input" | "output" | "temp" = "output"): string {
+    const params = new URLSearchParams({
+        filename,
+        subfolder,
+        type
+    })
+    const url = `http://${location.hostname}:8188` // TODO make configurable
+    return url + "/view?" + params
+}
+
 export function jsonToJsObject(json: string): string {
     // Try to parse, to see if it's real JSON
     JSON.parse(json);
diff --git a/src/lib/widgets/ImageCompareWidget.svelte b/src/lib/widgets/ImageCompareWidget.svelte
new file mode 100644
index 0000000..049748e
--- /dev/null
+++ b/src/lib/widgets/ImageCompareWidget.svelte
@@ -0,0 +1,80 @@
+<script lang="ts">
+ import { type WidgetLayout } from "$lib/stores/layoutState";
+ import { Block } from "@gradio/atoms";
+ import ImageComparison from "$lib/components/ImageComparison.svelte";
+ import { get, type Writable, writable } from "svelte/store";
+ import { isDisabled } from "./utils"
+ import type { SelectData } from "@gradio/utils";
+	import type { ComfyImageCompareNode, ImageCompareData } from "$lib/nodes/ComfyWidgetNodes";
+	import { convertFilenameToComfyURL } from "$lib/utils";
+	import { TabItem, Tabs } from "@gradio/tabs";
+
+ export let widget: WidgetLayout | null = null;
+ export let isMobile: boolean = false;
+ let node: ComfyImageCompareNode | null = null;
+ let nodeValue: Writable<ImageCompareData> | null = null;
+ let attrsChanged: Writable<number> | null = null;
+ let leftUrl: string = ""
+ let rightUrl: string = ""
+
+ $: widget && setNodeValue(widget);
+
+ function setNodeValue(widget: WidgetLayout) {
+     if (widget) {
+         node = widget.node as ComfyImageCompareNode
+         nodeValue = node.value;
+         attrsChanged = widget.attrsChanged;
+     }
+ };
+
+ const urlPattern = /^((http|https|ftp):\/\/)/;
+
+ $: updateUrls($nodeValue);
+
+ function updateUrls(value: ImageCompareData) {
+     leftUrl = ""
+     rightUrl = ""
+     console.warn("UPD", value)
+
+     if (typeof value[0] === "string") {
+         if (urlPattern.test(value[0]))
+             leftUrl = value[0]
+         else
+             leftUrl = convertFilenameToComfyURL(value[0])
+     }
+     if (typeof value[1] === "string") {
+         if (urlPattern.test(value[1]))
+             rightUrl = value[1]
+         else
+             rightUrl = convertFilenameToComfyURL(value[1])
+     }
+ }
+</script>
+
+<div class="wrapper comfy-compare-widget">
+    <Block>
+        <Tabs elem_classes={["gradio-tabs"]}>
+            <TabItem name="Slider">
+                <ImageComparison>
+                    {#if leftUrl && leftUrl != ""}
+                        {@const props = { slot: "first" }}
+                        <img {...props} alt="Left" src={leftUrl} />
+                    {/if}
+                    {#if rightUrl && leftUrl != ""}
+                        {@const props = { slot: "second" }}
+                        <img {...props} alt="Right" src={rightUrl} />
+                    {/if}
+                </ImageComparison>
+            </TabItem>
+        </Tabs>
+    </Block>
+</div>
+
+<style lang="scss">
+ .comfy-compare-widget {
+     max-width: 40rem;
+     img {
+         width: 100%;
+     }
+ }
+</style>