Tooldeon

Change image opacity

Choose a picture, drag the opacity slider and see the picture fade on a checkerboard. Download it as a PNG or WebP with real transparency. The change is made in your browser, so the file is not uploaded.

Everything happens in your browser. Your files are never uploaded.

Runs in your browser: nothing you enter is sent anywhere.

How to use it

  1. Choose a picture.
  2. Move the Opacity slider. 100 % leaves the picture unchanged, 0 % makes it fully transparent.
  3. Choose PNG or WebP and press Download image. The file name gets an -opacity-50 style suffix.

How it works

The picture is drawn on a canvas and every pixel’s alpha value (0 to 255) is multiplied by the opacity percentage and rounded to a whole number: 200 at 50 % becomes 100, and 255 at 30 % becomes 77. Colors are not touched. The preview uses a scaled copy; the download uses the original size.

Worked example

A logo at 100 % opacity placed over a photo hides it. Saved at 40 %, the same logo lets the photo show through, which is the usual way to prepare a watermark overlay.

Tips

  • Check the preview against both the light and dark squares of the checkerboard.
  • Keep the original: reducing opacity and saving again is not reversible in the saved file.
  • To fade only a background, use the background remover instead.

Frequently asked questions

Can I save the result as a JPG?

No. JPG has no transparency channel, so a picture with reduced opacity cannot be stored in it. Save PNG for the exact result, or WebP for a smaller file.

What happens to pictures that are already partly transparent?

Their transparency is multiplied by the new opacity. A pixel that is 50 % opaque becomes 25 % opaque at an opacity of 50 %. Fully transparent pixels stay transparent.

What is the difference between PNG and WebP here?

PNG is lossless and the file is usually larger. WebP is saved at high quality with a transparency channel and is usually smaller, but a few very old programs cannot open it.

Is the picture itself changed or only its look?

The saved file has new alpha values in every pixel. The colors are not changed, so on a white page 50 % opacity looks lighter, and on a dark page it looks darker.

More in Images

All tools in this category: Images ·Updated November 3, 2026

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