imagemagick is a free console software to create, edit, compose, or convert bitmap images.

Split image

Sometimes frames for animated characters come joined into a single image. For example, this is the image for the Skeleton death:

And the following command splits this image into a series of single pictures:

convert ./Skeleton_43x37.png -crop 43x37 skeleton_attack_%02d.png

Here

• ./Skeleton_43x37.png is an input file
• -crop 43x37 is the size of a single image
• skeleton_attack_%02d.png is a mask for result file names

Join images

That’s the opposite of previous task

convert +append ./skeleton_attack_00.png ./skeleton_attack_01.png ./jh.png
convert -append ./skeleton_attack_00.png ./skeleton_attack_01.png ./jv.png

Here +append joins the images horizontally (into a single row), and -append does similar thing but vertically (into a column).

Resize a gif

It’s quite hard to make a GIF smaller, and there can be some unexpected side effects.

However, this command could do the job:

convert input.gif -coalesce -scale 385x334 -fuzz 2% +dither -layers Optimize scaled.gif

Create an animation from files

Actually, the imagemagick isn’t a good tool for this task, it will be better to use ffmpeg:

ffmpeg -framerate 60 -pattern_type glob -i './skeleton_attack_*.png' c1.gif

Also, the animations in this articles were made by Peek tool in Ubuntu.

Remove some sequence from animation

A simpler way to remove some frames from a GIF is to split it into separate frames, remove some and join the rest ones back. However, this does not always work.

There are some other ways to complete this task. For example, you can use the gifsicle in Ubuntu.

This command keeps frames from 25th to 78th into another file:

gifsicle ./dragon_bones_mecha_03.gif '#25-78' > zz.gif

And this one just removes specified frames:

gifsicle ./dragon_bones_mecha_03.gif --delete '#01-25' > zz01.gif

Also, you can convert GIF files with this tool online.