diff --git a/web/extensions/core/maskeditor.js b/web/extensions/core/maskeditor.js
index 0d3faee58..4b0266f77 100644
--- a/web/extensions/core/maskeditor.js
+++ b/web/extensions/core/maskeditor.js
@@ -41,7 +41,7 @@ async function uploadMask(filepath, formData) {
 	});
 
 	ComfyApp.clipspace.imgs[ComfyApp.clipspace['selectedIndex']] = new Image();
-	ComfyApp.clipspace.imgs[ComfyApp.clipspace['selectedIndex']].src = "/view?" + new URLSearchParams(filepath).toString() + "&preview=jpeg";
+	ComfyApp.clipspace.imgs[ComfyApp.clipspace['selectedIndex']].src = "/view?" + new URLSearchParams(filepath).toString() + "&preview="+app.preview_format;
 
 	if(ComfyApp.clipspace.images)
 		ComfyApp.clipspace.images[ComfyApp.clipspace['selectedIndex']] = filepath;
diff --git a/web/scripts/app.js b/web/scripts/app.js
index d466675f4..8d25a9085 100644
--- a/web/scripts/app.js
+++ b/web/scripts/app.js
@@ -49,6 +49,12 @@ export class ComfyApp {
 		 * @type {boolean}
 		 */
 		this.shiftDown = false;
+
+		/**
+		 * file format for preview
+		 * @type {string}
+		 */
+		this.preview_format = "jpeg";
 	}
 
 	static isImageNode(node) {
@@ -371,7 +377,7 @@ export class ComfyApp {
 									const img = new Image();
 									img.onload = () => r(img);
 									img.onerror = () => r(null);
-									img.src = "/view?" + new URLSearchParams(src).toString() + "&preview=jpeg";
+									img.src = "/view?" + new URLSearchParams(src).toString() + "&preview="+app.preview_format;
 								});
 							})
 						).then((imgs) => {
diff --git a/web/scripts/widgets.js b/web/scripts/widgets.js
index cc493057e..fd50ce36f 100644
--- a/web/scripts/widgets.js
+++ b/web/scripts/widgets.js
@@ -303,7 +303,7 @@ export const ComfyWidgets = {
 				subfolder = name.substring(0, folder_separator);
 				name = name.substring(folder_separator + 1);
 			}
-			img.src = `/view?filename=${name}&type=input&subfolder=${subfolder}&preview=jpeg`;
+			img.src = `/view?filename=${name}&type=input&subfolder=${subfolder}&preview=${app.preview_format}`;
 			node.setSizeForImage?.();
 		}