Replace the small picture stored inside a single file: the preview in a photo, the thumbnail in a Word, Excel or PowerPoint document, or the cover art in an MP3, FLAC or MP4. Your file is processed in this browser tab and is never uploaded.
1. Choose the file
One file at a time. Supported: JPEG, DOCX, XLSX, PPTX, ODT, ODS, ODP, MP3, FLAC, M4A, MP4, MOV.
Click here or drop the file
2. Choose the new picture
PNG, JPEG, WebP or GIF. Any size; it is scaled down for you.
Click here or drop the picture
3. Check and set the size
Current thumbnail appears here
Current thumbnail
New thumbnail appears here
New thumbnail
4. Make the new copy
Your original is never changed. You get a new file with the thumbnail replaced, and the tool re-reads it to prove the new thumbnail is really inside.
Only the thumbnail is swapped. The photo, document text, audio and video are copied byte for byte. In an MP3 or FLAC every existing cover picture is replaced by the new one; in a JPEG the EXIF preview is replaced and all other EXIF data is kept.
Windows Explorer, macOS Finder and phones keep a cache of thumbnails. If the old picture still shows, rename the file or restart the viewer. Explorer for JPEG photos usually draws from the photo itself, so the EXIF preview mostly matters to cameras, galleries and metadata readers.
Not supported: PDF, HEIC, PNG, GIF, WebP, fragmented MP4 and ID3v2.2 tags. These are refused with a message rather than guessed at.
A JPEG preview must fit inside a 64 KB EXIF block, so its size choices stop at 200 pixels.