I have a number of photos. I want to add these images togther pixel-wise (not mean or median). I have Imagemagick installed, and I tried:
composite -compose plus IMG* ~/Desktop/sum.png
But the output image
wasn't noticeably brighter than the input images:
Since I have 30 input images, I expected the output to be much brighter.
Why isn't this working, and how do I sum images, using either Imagemagick, or other free tool?
imagemagickwill only merge two images in the way you've described. If you want to merge more, you can write a relatively simple bash script to take in a directory and merge all images through a series of merges. i.e.
((im1 + im2) + im3) + im4 ...