diff --git a/packages/pi-coding-agent/src/modes/interactive/components/tool-execution.ts b/packages/pi-coding-agent/src/modes/interactive/components/tool-execution.ts
index a5f80da87..1b1c547d9 100644
--- a/packages/pi-coding-agent/src/modes/interactive/components/tool-execution.ts
+++ b/packages/pi-coding-agent/src/modes/interactive/components/tool-execution.ts
@@ -3,6 +3,7 @@ import {
 	Container,
 	getCapabilities,
 	Image,
+	type ImageDimensions,
 	imageFallback,
 	Spacer,
 	Text,
@@ -88,6 +89,9 @@ export class ToolExecutionComponent extends Container {
 	private editDiffArgsKey?: string; // Track which args the preview is for
 	// Cached converted images for Kitty protocol (which requires PNG), keyed by index
 	private convertedImages: Map<number, { data: string; mimeType: string }> = new Map();
+	// Cached resolved image dimensions to avoid re-triggering async parsing
+	// when updateDisplay() recreates Image components (#3455).
+	private resolvedImageDimensions: Map<number, ImageDimensions> = new Map();
 	// Incremental syntax highlighting cache for write tool call args
 	private writeHighlightCache?: WriteHighlightCache;
 	// When true, this component intentionally renders no lines
@@ -481,16 +485,28 @@ export class ToolExecutionComponent extends Container {
 					const spacer = new Spacer(1);
 					this.addChild(spacer);
 					this.imageSpacers.push(spacer);
+					// Pass cached dimensions to avoid re-triggering async parsing
+					// when updateDisplay() recreates Image components (#3455).
+					const cachedDims = this.resolvedImageDimensions.get(i);
 					const imageComponent = new Image(
 						imageData,
 						imageMimeType,
 						{ fallbackColor: (s: string) => theme.fg("toolOutput", s) },
 						{ maxWidthCells: 60 },
+						cachedDims,
 					);
-					imageComponent.setOnDimensionsResolved(() => {
-						this.updateDisplay();
-						this.ui.requestRender();
-					});
+					if (!cachedDims) {
+						const imgIdx = i;
+						imageComponent.setOnDimensionsResolved(() => {
+							// Cache resolved dimensions so future updateDisplay() calls
+							// don't re-trigger async parsing → infinite loop (#3455).
+							const dims = imageComponent.getDimensions?.();
+							if (dims) this.resolvedImageDimensions.set(imgIdx, dims);
+							// Just re-render — don't call updateDisplay() which would
+							// destroy and recreate all Image components.
+							this.ui.requestRender();
+						});
+					}
 					this.imageComponents.push(imageComponent);
 					this.addChild(imageComponent);
 				}
diff --git a/packages/pi-tui/src/components/image.test.ts b/packages/pi-tui/src/components/image.test.ts
new file mode 100644
index 000000000..3bef04a85
--- /dev/null
+++ b/packages/pi-tui/src/components/image.test.ts
@@ -0,0 +1,36 @@
+/**
+ * Regression test for #3455: Image component must not trigger infinite
+ * re-render loop when dimensions resolve in cmux sessions.
+ */
+
+import { describe, test } from "node:test";
+import assert from "node:assert/strict";
+import { Image } from "./image.js";
+
+describe("Image component (#3455)", () => {
+	const theme = { fallbackColor: (s: string) => s };
+
+	test("getDimensions returns undefined before resolution", () => {
+		// Pass explicit dimensions to avoid async parsing
+		const img = new Image("base64data", "image/png", theme, {});
+		// Without explicit dims, getDimensions should be undefined until async resolve
+		// But we can't easily test async here, so verify the method exists
+		assert.equal(typeof img.getDimensions, "function");
+	});
+
+	test("getDimensions returns dimensions when provided at construction", () => {
+		const dims = { widthPx: 100, heightPx: 200 };
+		const img = new Image("base64data", "image/png", theme, {}, dims);
+		const result = img.getDimensions();
+		assert.deepEqual(result, dims, "Should return provided dimensions");
+	});
+
+	test("onDimensionsResolved callback is not called when dimensions provided", () => {
+		let callCount = 0;
+		const dims = { widthPx: 100, heightPx: 200 };
+		const img = new Image("base64data", "image/png", theme, {}, dims);
+		img.setOnDimensionsResolved(() => { callCount++; });
+		// With pre-resolved dims, the async path is skipped entirely
+		assert.equal(callCount, 0, "Callback should not fire for pre-resolved dimensions");
+	});
+});
diff --git a/packages/pi-tui/src/components/image.ts b/packages/pi-tui/src/components/image.ts
index c789a0a5b..814167605 100644
--- a/packages/pi-tui/src/components/image.ts
+++ b/packages/pi-tui/src/components/image.ts
@@ -72,6 +72,11 @@ export class Image implements Component {
 		return this.imageId;
 	}
 
+	/** Get the resolved image dimensions (for caching across recreations). */
+	getDimensions(): ImageDimensions | undefined {
+		return this.dimensionsResolved ? this.dimensions : undefined;
+	}
+
 	invalidate(): void {
 		this.cachedLines = undefined;
 		this.cachedWidth = undefined;