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ToolSuite
Image Tools

Add Alpha Channel

Give an image transparency - uniform, or derived from its own brightness.

or drag it here

image/* · up to 40 MB

Processed in your browser

Fill in the form and press “Add alpha” to see the result here.

How to use it

  1. 1Select your image, or drag and drop it onto the upload area.
  2. 2Adjust the options if you need something other than the defaults.
  3. 3Press the button. The image is processed on your device - nothing is uploaded.
  4. 4Download the result, or drop in another file to do it again.

About the Add Alpha Channel

Uniform opacity is what you want for a watermark. Brightness-based alpha turns a black-on-white logo into a mask, which is a quick way to make one usable over any background.

The result is always PNG, because JPEG has no alpha channel. Saving transparency as JPEG silently flattens it - usually onto black, which is rarely what anyone intended.

Questions people ask

Is your image uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your image never leaves your device. You can confirm it by opening your browser's network panel while the tool runs, or by disconnecting from the internet after the page has loaded.

Is it free, and do I need an account?

Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.