Edit your GIF animations with the GIF Alpha Mask Generator. Upload a GIF, apply your changes, and download the result. All processing runs entirely in your browser — your files are never uploaded to any server.
Drop a GIF here or click to upload
Supports animated and static GIF files
About
Wondering which parts of a GIF are actually transparent and which are opaque? This tool generates an alpha mask — a black-and-white version of your animation where white represents visible pixels and black represents transparent ones. It is incredibly useful for debugging transparency issues, verifying cutouts, or preparing assets for compositing work.
Features
Instantly converts each frame into a clear black-and-white transparency map
Makes it easy to spot unwanted transparent spots or missed edges at a glance
Works across all frames so you can catch transparency that changes mid-animation
Processes everything in your browser with zero uploads required
Guide
Upload the GIF you want to inspect
The tool immediately generates an alpha mask for every frame in the animation
Browse through the frames to see which areas are transparent (black) and which are opaque (white)
Download the alpha mask GIF if you need it for further editing or documentation
Pro Tips
Use this tool to verify that a background removal actually worked before sharing the GIF
If you see unexpected white patches in the mask, your GIF might have semi-transparent pixels that are not fully see-through
Pair this with the transparency checker to get both a visual map and a quick yes-or-no answer
FAQ
Upload your GIF and configure the settings. The tool processes everything in your browser using JavaScript, so your files stay private and the result is ready to download instantly.
Yes. All processing happens locally in your browser. Your GIF files are never sent to any server, ensuring complete privacy.
There is no hard limit. Processing speed depends on your device — most modern browsers handle GIFs up to 30–50 MB without issues.
Related
Upload your GIF above and get started. It takes seconds, costs nothing, and your file never leaves your browser.