I am looking for a free online service that can cut a GIF file.
E.g. if the GIF file has a length of 20 seconds, I would like to be able to create a new GIF file that would correspond to the old one from second 5 to 15.
It isn't perfect but LunaPic should do the job.
Edit Gif Animation
Animation Ordering / Edit frames
You might also want to look at
frame timing to see the exact timing between frames to know how many to delete.
Not online but mentioned because it's the only way I could find to remove a range of frames in a single command. For linux,
gifsicle is a very useful tool:
#see how many frames the gif has gifsicle --info mygif.gif #delete the last few gifsicle mygif.gif --delete '#200-' -O3 > out.gif #or only use a range of frames (doesn't work well for me) gifsicle -U mygif.gif '#100-200' -O3 > out.gif
-U "unoptimize" is very important as some gifs use transparency and a bunch of other methods to encode deltas between frames rather than entirely new frames. This would cause artefacts when the original frames are missing.
-O3 re-optimizes the result.