rmagick-sprite allows you to easily slice up a spritesheet into Magick::Images.

The thought is that a spreadsheet contains many of a character’s actions (standing, walking, jumping, etc..) which consist of many frames. This provides a DSL for defining those actions and where on the spritesheet each action’s frames are located. Then, you are free to use these images in your favorite game library, save each frame as separate images, or even save each action as an animated GIF. Check it out!