How do I rip sprites?

I'm trying to rip sprites out of a gba game, but how would I go about doing that? I've already tried opening the archive with 7zip, but it didnt work. On the same note, what would be a good program for arranging 3d models from a NDS game? Im trying to make myself a screenshot thing, and want to replace some sprites and 3d animations with sutom ones for a video im doing.

As far as I know, there are two ways you can rip sprites. The simplest way is to just take a screenshot of each sprite you want. This can be tedious, especially if you're after a complete sheet. The best way to go about it requires that your emulator has a "resource viewer" or similar tool, which will allow you to view all the tiles, sprites, and other data that are currently in RAM. The sheet itself should be easily found. From there, you can use your OS or an app like GIMP to take the screenshot (or save the entire sheet, if the tool allows).

I hope this helps.