diff --git a/src/lib/modules/thumbnail.ts b/src/lib/modules/thumbnail.ts
index 1a24b5d..873772e 100644
--- a/src/lib/modules/thumbnail.ts
+++ b/src/lib/modules/thumbnail.ts
@@ -42,6 +42,30 @@ const generateImageThumbnail = (imageUrl: string) => {
   });
 };
 
+export const captureVideoThumbnail = (video: HTMLVideoElement) => {
+  return new Promise<Blob>((resolve, reject) => {
+    const canvas = document.createElement("canvas");
+    const { width, height } = scaleSize(video.videoWidth, video.videoHeight, 250);
+
+    canvas.width = width;
+    canvas.height = height;
+
+    const context = canvas.getContext("2d");
+    if (!context) {
+      return reject(new Error("Failed to generate thumbnail"));
+    }
+
+    context.drawImage(video, 0, 0, width, height);
+    canvas.toBlob((blob) => {
+      if (blob) {
+        resolve(blob);
+      } else {
+        reject(new Error("Failed to generate thumbnail"));
+      }
+    }, "image/webp");
+  });
+};
+
 const generateVideoThumbnail = (videoUrl: string, time = 0) => {
   return new Promise<Blob>((resolve, reject) => {
     const video = document.createElement("video");
@@ -49,25 +73,7 @@ const generateVideoThumbnail = (videoUrl: string, time = 0) => {
       video.currentTime = time;
     };
     video.onseeked = () => {
-      const canvas = document.createElement("canvas");
-      const { width, height } = scaleSize(video.videoWidth, video.videoHeight, 250);
-
-      canvas.width = width;
-      canvas.height = height;
-
-      const context = canvas.getContext("2d");
-      if (!context) {
-        return reject(new Error("Failed to generate thumbnail"));
-      }
-
-      context.drawImage(video, 0, 0, width, height);
-      canvas.toBlob((blob) => {
-        if (blob) {
-          resolve(blob);
-        } else {
-          reject(new Error("Failed to generate thumbnail"));
-        }
-      }, "image/webp");
+      captureVideoThumbnail(video).then(resolve).catch(reject);
     };
     video.onerror = reject;
 
diff --git a/src/routes/(fullscreen)/file/[id]/+page.svelte b/src/routes/(fullscreen)/file/[id]/+page.svelte
index 325122f..61465bd 100644
--- a/src/routes/(fullscreen)/file/[id]/+page.svelte
+++ b/src/routes/(fullscreen)/file/[id]/+page.svelte
@@ -11,15 +11,18 @@
     type FileInfo,
     type CategoryInfo,
   } from "$lib/modules/filesystem";
+  import { captureVideoThumbnail } from "$lib/modules/thumbnail";
   import { fileDownloadStatusStore, isFileDownloading, masterKeyStore } from "$lib/stores";
   import AddToCategoryBottomSheet from "./AddToCategoryBottomSheet.svelte";
   import DownloadStatus from "./DownloadStatus.svelte";
   import {
     requestFileRemovalFromCategory,
     requestFileDownload,
+    requestThumbnailUpload,
     requestFileAdditionToCategory,
   } from "./service";
 
+  import IconCamera from "~icons/material-symbols/camera";
   import IconClose from "~icons/material-symbols/close";
   import IconAddCircle from "~icons/material-symbols/add-circle";
 
@@ -40,6 +43,7 @@
   let isDownloadRequested = $state(false);
   let viewerType: "image" | "video" | undefined = $state();
   let fileBlobUrl: string | undefined = $state();
+  let videoElement: HTMLVideoElement | undefined = $state();
 
   const updateViewer = async (buffer: ArrayBuffer, contentType: string) => {
     const fileBlob = new Blob([buffer], { type: contentType });
@@ -55,6 +59,11 @@
     return fileBlob;
   };
 
+  const updateThumbnail = async (dataKey: CryptoKey, dataKeyVersion: Date) => {
+    const thumbnail = await captureVideoThumbnail(videoElement!);
+    await requestThumbnailUpload(data.id, thumbnail, dataKey, dataKeyVersion);
+  };
+
   const addToCategory = async (categoryId: number) => {
     await requestFileAdditionToCategory(data.id, categoryId);
     isAddToCategoryBottomSheetOpen = false;
@@ -133,8 +142,17 @@
           {/if}
         {:else if viewerType === "video"}
           {#if fileBlobUrl}
-            <!-- svelte-ignore a11y_media_has_caption -->
-            <video src={fileBlobUrl} controls></video>
+            <div class="flex flex-col space-y-2">
+              <!-- svelte-ignore a11y_media_has_caption -->
+              <video bind:this={videoElement} src={fileBlobUrl} controls muted></video>
+              <IconEntryButton
+                icon={IconCamera}
+                onclick={() => updateThumbnail($info.dataKey!, $info.dataKeyVersion!)}
+                class="w-full"
+              >
+                이 장면을 썸네일로 설정하기
+              </IconEntryButton>
+            </div>
           {:else}
             {@render viewerLoading("비디오를 불러오고 있어요.")}
           {/if}
diff --git a/src/routes/(fullscreen)/file/[id]/service.ts b/src/routes/(fullscreen)/file/[id]/service.ts
index ccedcd1..83a57c6 100644
--- a/src/routes/(fullscreen)/file/[id]/service.ts
+++ b/src/routes/(fullscreen)/file/[id]/service.ts
@@ -1,9 +1,37 @@
 import { callPostApi } from "$lib/hooks";
-import type { CategoryFileAddRequest } from "$lib/server/schemas";
+import { encryptData } from "$lib/modules/crypto";
+import { storeFileThumbnailCache } from "$lib/modules/file";
+import type { CategoryFileAddRequest, FileThumbnailUploadRequest } from "$lib/server/schemas";
 
 export { requestCategoryCreation, requestFileRemovalFromCategory } from "$lib/services/category";
 export { requestFileDownload } from "$lib/services/file";
 
+export const requestThumbnailUpload = async (
+  fileId: number,
+  thumbnail: Blob,
+  dataKey: CryptoKey,
+  dataKeyVersion: Date,
+) => {
+  const thumbnailBuffer = await thumbnail.arrayBuffer();
+  const thumbnailEncrypted = await encryptData(thumbnailBuffer, dataKey);
+
+  const form = new FormData();
+  form.set(
+    "metadata",
+    JSON.stringify({
+      dekVersion: dataKeyVersion.toISOString(),
+      contentIv: thumbnailEncrypted.iv,
+    } satisfies FileThumbnailUploadRequest),
+  );
+  form.set("content", new Blob([thumbnailEncrypted.ciphertext]));
+
+  const res = await fetch(`/api/file/${fileId}/thumbnail/upload`, { method: "POST", body: form });
+  if (!res.ok) return false;
+
+  storeFileThumbnailCache(fileId, thumbnailBuffer); // Intended
+  return true;
+};
+
 export const requestFileAdditionToCategory = async (fileId: number, categoryId: number) => {
   const res = await callPostApi<CategoryFileAddRequest>(`/api/category/${categoryId}/file/add`, {
     file: fileId,