How to use ImageMagick to subtract an image from another?

Question

I have these two images:

_{(source: free.fr )}

_{(source: free.fr )}

How can I use imagemagick to remove the background (second image) from the first?

Cheers

Remy

Here I made you the last but simple example:

Transparent overlay http://noosphere.ionyse.com/transparent_example/transparent_difference.png Background http://noosphere.ionyse.com/transparent_example/background.png

Example 1 http://noosphere.ionyse.com/transparent_example/background-example.png Example 2 http://noosphere.ionyse.com/transparent_example/background-example2.png

Here you see that wherever I place a transparent overlay on the background, I get a perfect match using the opacity of the PNG overlay.

I would like to be able to calculate this image overlay. Do you think this is possible with ImageMagick?

Answer 1

This is explained here. How to save DIFFERENCES between two images? .

Another useful link: http://www.imagemagick.org/Usage/compare/#difference