How to merge images in command line? [closed]

You can also try ImageMagic which is great for creating CSS sprites. Some tutorial about it here.

Example (vertical sprite):

convert image1.png image2.png image3.png -append result/result-sprite.png

Example (horizontal sprite):

convert image1.png image2.png image3.png +append result/result-sprite.png

You can also use GraphicsMagick, a lighter and faster fork of ImageMagick:

gm convert image1.png image2.png -append combined.png

A simple time comparison of merging 12 images:

time convert image{1..12}.jpg -append test.jpgreal    0m3.178suser    0m3.850ssys     0m0.376stime gm convert image{1..12}.jpg -append test.jpgreal    0m1.912suser    0m2.198ssys     0m0.766s

GraphicsMagick is almost twice as fast as ImageMagick.

Use the pnmcat of the netpbm-package.

You probably have to convert your input files to and fro for using it:

pnmcat -lr <(pngtopnm 1.png) <(pngtopnm 2.png) | pnmtopng > all.png

EDIT:As user Hashbrown pointed out in a comment, this might have trouble with different sizes and/or transparency in the PNGs. To circumvent that he came up with this solution (just copying it here because the Q is closed and new answers cannot be added):

pnmcat -jleft -tb \    <(pngtopnm image139.png) \    <(pngtopnm image73.png) \| pnmtopng \    -alpha <(pnmcat -black -jleft -tb \        <(pngtopnm -alpha image139.png) \        <(pngtopnm -alpha image73.png) \    ) \>test.png

I didn't test that solution, though.