diff --git a/src/lib/modules/thumbnail.ts b/src/lib/modules/thumbnail.ts
index 9c009bd..2d5cd55 100644
--- a/src/lib/modules/thumbnail.ts
+++ b/src/lib/modules/thumbnail.ts
@@ -32,7 +32,7 @@ const capture = (
 
     drawer(context, scaledWidth, scaledHeight);
     canvas.toBlob((blob) => {
-      if (blob) {
+      if (blob && blob.type === "image/webp") {
         resolve(blob);
       } else {
         reject(new Error("Failed to generate thumbnail"));
@@ -83,18 +83,26 @@ const generateVideoThumbnail = (videoUrl: string, time = 0) => {
 export const generateThumbnail = async (fileBuffer: ArrayBuffer, fileType: string) => {
   let url;
   try {
-    if (fileType === "image/heic") {
-      const { default: heic2any } = await import("heic2any");
-      url = URL.createObjectURL(
-        (await heic2any({
-          blob: new Blob([fileBuffer], { type: fileType }),
-          toType: "image/png",
-        })) as Blob,
-      );
-      return await generateImageThumbnail(url);
-    } else if (fileType.startsWith("image/")) {
-      url = URL.createObjectURL(new Blob([fileBuffer], { type: fileType }));
-      return await generateImageThumbnail(url);
+    if (fileType.startsWith("image/")) {
+      const fileBlob = new Blob([fileBuffer], { type: fileType });
+      url = URL.createObjectURL(fileBlob);
+
+      try {
+        return await generateImageThumbnail(url);
+      } catch {
+        URL.revokeObjectURL(url);
+        url = undefined;
+
+        if (fileType === "image/heic") {
+          const { default: heic2any } = await import("heic2any");
+          url = URL.createObjectURL(
+            (await heic2any({ blob: fileBlob, toType: "image/png" })) as Blob,
+          );
+          return await generateImageThumbnail(url);
+        } else {
+          return null;
+        }
+      }
     } else if (fileType.startsWith("video/")) {
       url = URL.createObjectURL(new Blob([fileBuffer], { type: fileType }));
       return await generateVideoThumbnail(url);
diff --git a/src/routes/(fullscreen)/file/[id]/+page.svelte b/src/routes/(fullscreen)/file/[id]/+page.svelte
index 61465bd..4047e7c 100644
--- a/src/routes/(fullscreen)/file/[id]/+page.svelte
+++ b/src/routes/(fullscreen)/file/[id]/+page.svelte
@@ -43,22 +43,31 @@
   let isDownloadRequested = $state(false);
   let viewerType: "image" | "video" | undefined = $state();
   let fileBlobUrl: string | undefined = $state();
+  let heicBlob: Blob | undefined = $state();
   let videoElement: HTMLVideoElement | undefined = $state();
 
   const updateViewer = async (buffer: ArrayBuffer, contentType: string) => {
     const fileBlob = new Blob([buffer], { type: contentType });
-    if (contentType === "image/heic") {
-      const { default: heic2any } = await import("heic2any");
-      fileBlobUrl = URL.createObjectURL(
-        (await heic2any({ blob: fileBlob, toType: "image/jpeg" })) as Blob,
-      );
-    } else if (viewerType) {
+    if (viewerType) {
       fileBlobUrl = URL.createObjectURL(fileBlob);
+      heicBlob = contentType === "image/heic" ? fileBlob : undefined;
     }
-
     return fileBlob;
   };
 
+  const convertHeicToJpeg = async () => {
+    if (!heicBlob) return;
+
+    URL.revokeObjectURL(fileBlobUrl!);
+    fileBlobUrl = undefined;
+
+    const { default: heic2any } = await import("heic2any");
+    fileBlobUrl = URL.createObjectURL(
+      (await heic2any({ blob: heicBlob, toType: "image/jpeg" })) as Blob,
+    );
+    heicBlob = undefined;
+  };
+
   const updateThumbnail = async (dataKey: CryptoKey, dataKeyVersion: Date) => {
     const thumbnail = await captureVideoThumbnail(videoElement!);
     await requestThumbnailUpload(data.id, thumbnail, dataKey, dataKeyVersion);
@@ -136,7 +145,7 @@
 
         {#if viewerType === "image"}
           {#if fileBlobUrl}
-            <img src={fileBlobUrl} alt={$info.name} />
+            <img src={fileBlobUrl} alt={$info.name} onerror={convertHeicToJpeg} />
           {:else}
             {@render viewerLoading("이미지를 불러오고 있어요.")}
           {/if}