diff --git a/__init__.py b/__init__.py
index b09db8d..595f093 100644
--- a/__init__.py
+++ b/__init__.py
@@ -540,6 +540,63 @@ async def delete_model_preview(request):
     return web.json_response(result)
 
 
+def correct_image_extensions(root_dir):
+    detected_image_count = 0
+    corrected_image_count = 0
+    for root, dirs, files in os.walk(root_dir):
+        for file_name in files:
+            file_path = root + os.path.sep + file_name
+            image_format = None
+            try:
+                with Image.open(file_path) as image:
+                    image_format = image.format
+            except:
+                continue
+            image_path = file_path
+            image_dir_and_name, image_ext = os.path.splitext(image_path)
+            if not image_format_is_equal(image_format, image_ext):
+                detected_image_count += 1
+                corrected_image_path = image_dir_and_name + "." + image_format.lower()
+                if os.path.exists(corrected_image_path):
+                    print("WARNING: '" + image_path + "' has wrong extension!")
+                else:
+                    try:
+                        os.rename(image_path, corrected_image_path)
+                    except:
+                        print("WARNING: Unable to rename '" + image_path + "'!")
+                        continue
+                    ext0 = os.path.splitext(image_path)[1]
+                    ext1 = os.path.splitext(corrected_image_path)[1]
+                    print(f"({ext0} -> {ext1}): {corrected_image_path}")
+                    corrected_image_count += 1
+    return (detected_image_count, corrected_image_count)
+
+
+@server.PromptServer.instance.routes.get("/model-manager/preview/correct-extensions")
+async def correct_preview_extensions(request):
+    result = { "success": False }
+
+    detected = 0
+    corrected = 0
+
+    model_types = os.listdir(comfyui_model_uri)
+    model_types.remove("configs")
+    model_types.sort()
+
+    for model_type in model_types:
+        for base_path_index, model_base_path in enumerate(folder_paths_get_folder_paths(model_type)):
+            if not os.path.exists(model_base_path): # TODO: Bug in main code? ("ComfyUI\output\checkpoints", "ComfyUI\output\clip", "ComfyUI\models\t2i_adapter", "ComfyUI\output\vae")
+                continue
+            d, c = correct_image_extensions(model_base_path)
+            detected += d
+            corrected += c
+
+    result["success"] = True
+    result["detected"] = detected
+    result["corrected"] = corrected
+    return web.json_response(result)
+
+
 @server.PromptServer.instance.routes.get("/model-manager/models/list")
 async def get_model_list(request):
     use_safetensor_thumbnail = (
diff --git a/web/model-manager.css b/web/model-manager.css
index e3860ac..cb54d74 100644
--- a/web/model-manager.css
+++ b/web/model-manager.css
@@ -628,6 +628,7 @@
 .model-manager .tag-generator-settings > div {
     display: flex;
     flex-direction: row;
+    flex-wrap: wrap;
     align-items: center;
     gap: 8px;
     margin: 16px 0;
@@ -635,7 +636,7 @@
 
 .model-manager .model-manager-settings button {
     height: 40px;
-    width: 120px;
+    min-width: 120px;
     justify-content: center;
 }
 
diff --git a/web/model-manager.js b/web/model-manager.js
index 538b837..7a8fc6e 100644
--- a/web/model-manager.js
+++ b/web/model-manager.js
@@ -3680,6 +3680,32 @@ class SettingsView {
         }).element;
         this.elements.saveButton = saveButton;
         
+        const correctPreviewsButton = new ComfyButton({
+            content: "Fix Preview Extensions",
+            tooltip: "Correct image extensions in all model directories",
+            action: async(e) => {
+                const [button, icon, span] = comfyButtonDisambiguate(e.target);
+                button.disabled = true;
+                const data = await request(
+                    "/model-manager/preview/correct-extensions")
+                .catch((err) => {
+                    return { "success": false };
+                });
+                const success = data["success"];
+                if (success) {
+                    const detectPlural = data["detected"] === 1 ? "" : "s";
+                    const correctPlural = data["corrected"] === 1 ? "" : "s";
+                    const message = `Detected ${data["detected"]} extension${detectPlural}.\nCorrected ${data["corrected"]} extension${correctPlural}.`;
+                    window.alert(message);
+                }
+                comfyButtonAlert(e.target, success);
+                if (data["corrected"] > 0) {
+                    await this.reload(true);
+                }
+                button.disabled = false;
+            },
+        }).element;
+        
         $el("div.model-manager-settings", {
             $: (el) => (this.element = el),
         }, [
@@ -3822,6 +3848,10 @@ class SettingsView {
                     min: 1,
                 }),
             ]),
+            $el("h2", ["Preview"]),
+            $el("div", [
+                correctPreviewsButton,
+            ]),
         ]);
     }
 }