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Channel Merger

Load three greyscale images and recombine them into one RGB colour image.

Merge three channels

Download RGB
Sources: —
The red channel of each greyscale source becomes one colour channel of the merged image on a local canvas.

How to use the Channel Merger

  1. Load a greyscale image into the red, green and blue source slots.
  2. Click Merge channels to combine them into one colour image.
  3. Download the merged RGB result as a PNG file.

Features

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Frequently Asked Questions

Common questions about the free online channel merger.

It rebuilds a colour image from separate red, green and blue greyscale files, which is common in scientific imaging and compositing work.
The red channel of each file is used, because in a greyscale image the red, green and blue values are identical.
The smallest width and height are used and the other sources are scaled to fit, so no channel is cropped away or stretched unevenly.
Yes, but only their red channel is read. For predictable results feed the tool three greyscale files exported by the channel splitter.
No. All three files are decoded in your browser and combined on a local canvas, so nothing is ever transmitted.
The first file becomes the red channel, the second becomes green and the third becomes blue, exactly as the labels say.
Yes. The clear all button empties every source slot so you can start a new merge with a different set of files.
The result is saved as a PNG file, which keeps the exact channel values without extra JPEG compression artefacts.
Yes. The merger is fully responsive and works in any modern mobile browser, loading pictures from the camera roll.

Last updated: October 10, 2026