diff --git a/web/app/account/(commonLayout)/account-page/AvatarWithEdit.tsx b/web/app/account/(commonLayout)/account-page/AvatarWithEdit.tsx
index 84d019f174c..c69842eb931 100644
--- a/web/app/account/(commonLayout)/account-page/AvatarWithEdit.tsx
+++ b/web/app/account/(commonLayout)/account-page/AvatarWithEdit.tsx
@@ -16,7 +16,7 @@ import Divider from '@/app/components/base/divider'
 import { useLocalFileUploader } from '@/app/components/base/image-uploader/hooks'
 import { DISABLE_UPLOAD_IMAGE_AS_ICON } from '@/config'
 import { updateUserProfile } from '@/service/common'
-import { createCroppedAvatarImage } from './avatar-image'
+import { createAvatarImageFile, createCroppedAvatarImage } from './avatar-image'
 
 type InputImageInfo =
   | { file: File }
@@ -111,7 +111,7 @@ const AvatarWithEdit = ({ onSave, ...props }: AvatarWithEditProps) => {
       inputImageInfo.croppedAreaPixels,
       inputImageInfo.fileName,
     )
-    const file = new File([blob], inputImageInfo.fileName, { type: blob.type })
+    const file = createAvatarImageFile(blob, inputImageInfo.fileName)
     handleLocalFileUpload(file)
   }, [handleLocalFileUpload, inputImageInfo])
 
diff --git a/web/app/account/(commonLayout)/account-page/__tests__/AvatarWithEdit.spec.tsx b/web/app/account/(commonLayout)/account-page/__tests__/AvatarWithEdit.spec.tsx
index f57b5ac4328..96bcab92141 100644
--- a/web/app/account/(commonLayout)/account-page/__tests__/AvatarWithEdit.spec.tsx
+++ b/web/app/account/(commonLayout)/account-page/__tests__/AvatarWithEdit.spec.tsx
@@ -45,9 +45,13 @@ vi.mock('@/app/components/base/image-uploader/hooks', () => ({
   }),
 }))
 
-vi.mock('../avatar-image', () => ({
-  createCroppedAvatarImage: vi.fn(),
-}))
+vi.mock('../avatar-image', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('../avatar-image')>()
+  return {
+    ...actual,
+    createCroppedAvatarImage: vi.fn(),
+  }
+})
 
 const mockedCreateCroppedAvatarImage = vi.mocked(createCroppedAvatarImage)
 
diff --git a/web/app/account/(commonLayout)/account-page/__tests__/avatar-image.spec.ts b/web/app/account/(commonLayout)/account-page/__tests__/avatar-image.spec.ts
index 74308136813..5b22a3c709f 100644
--- a/web/app/account/(commonLayout)/account-page/__tests__/avatar-image.spec.ts
+++ b/web/app/account/(commonLayout)/account-page/__tests__/avatar-image.spec.ts
@@ -1,6 +1,10 @@
 import type { Area } from 'react-easy-crop'
 import { createImage } from '@/app/components/base/app-icon-picker/utils'
-import { createCroppedAvatarImage, getBoundedAvatarImageSize } from '../avatar-image'
+import {
+  createAvatarImageFile,
+  createCroppedAvatarImage,
+  getBoundedAvatarImageSize,
+} from '../avatar-image'
 
 vi.mock('@/app/components/base/app-icon-picker/utils', async (importOriginal) => {
   const actual =
@@ -58,4 +62,13 @@ describe('avatar image', () => {
     expect(context.drawImage).toHaveBeenCalledWith(image, 40, 20, 1000, 1000, 0, 0, 256, 256)
     expect(canvas.toBlob).toHaveBeenCalledWith(expect.any(Function), 'image/png', 0.85)
   })
+
+  it('matches the file extension to the browser output type', () => {
+    const blob = new Blob(['avatar'], { type: 'image/png' })
+
+    const file = createAvatarImageFile(blob, 'avatar.webp')
+
+    expect(file.name).toBe('avatar.png')
+    expect(file.type).toBe('image/png')
+  })
 })
diff --git a/web/app/account/(commonLayout)/account-page/avatar-image.ts b/web/app/account/(commonLayout)/account-page/avatar-image.ts
index 84240d4211a..8d5b66b1d72 100644
--- a/web/app/account/(commonLayout)/account-page/avatar-image.ts
+++ b/web/app/account/(commonLayout)/account-page/avatar-image.ts
@@ -3,6 +3,11 @@ import { createImage, getMimeType } from '@/app/components/base/app-icon-picker/
 
 const AVATAR_IMAGE_MAX_SIZE = 256
 const AVATAR_IMAGE_QUALITY = 0.85
+const AVATAR_IMAGE_EXTENSION_BY_MIME_TYPE: Record<string, string> = {
+  'image/jpeg': 'jpg',
+  'image/png': 'png',
+  'image/webp': 'webp',
+}
 
 export const getBoundedAvatarImageSize = (
   crop: Pick<Area, 'width' | 'height'>,
@@ -55,3 +60,15 @@ export const createCroppedAvatarImage = async (
     )
   })
 }
+
+export const createAvatarImageFile = (blob: Blob, fileName: string) => {
+  const extension = AVATAR_IMAGE_EXTENSION_BY_MIME_TYPE[blob.type]
+
+  if (!extension || getMimeType(fileName) === blob.type)
+    return new File([blob], fileName, { type: blob.type })
+
+  const extensionStart = fileName.lastIndexOf('.')
+  const baseName = extensionStart > 0 ? fileName.slice(0, extensionStart) : fileName
+
+  return new File([blob], `${baseName}.${extension}`, { type: blob.type })
+}