Merge two images with transparency in imagemagick

Solution 1:

Imagemagick is a complex tool with a lot of options.
In the example you posted it seems that to the first image is superimposed (overlapped) a copy flipped with some transparency level. All actions that you can do at the price of a complicate commandline.

Let's suppose, for sake of simplicity, that you have just ready the two images. Give it a look to ^[1],[2] to understand better how it works. In the second reference ^[2] you can have a guess by examples about the methods available in Imagemagick to add two images.

Probably the -dissolve ^[3] or the -blend ^[4] option is what you are searching for:

composite -dissolve 50 -gravity Center a.jpg b.jpg -alpha Set result.jpg

Another way to do it can be ^[5]

convert FUfstEv.jpg  \
\( ChYNTch.jpg -alpha set -channel a -evaluate set 50% +channel \) \
-gravity center -compose over -composite result1.jpg

Additional operation may have to be added to scale the image if needed... As additional reference you can see ^[n]. See again this page ^[5] for some examples.

In general the syntax of the dissolve option can be similar to the following one:

composite -dissolve {argument} -gravity Center \
1.gif 2.gif -alpha Set {result}