diff --git a/web/scripts/app.js b/web/scripts/app.js
index 8d25a9085..7d49d5e75 100644
--- a/web/scripts/app.js
+++ b/web/scripts/app.js
@@ -54,7 +54,7 @@ export class ComfyApp {
 		 * file format for preview
 		 * @type {string}
 		 */
-		this.preview_format = "jpeg";
+		this.preview_format = "webp";
 	}
 
 	static isImageNode(node) {