Pictures of the same character repeatedly in the same image, either copied and pasted or redrawn, with minor variations such as changes in outfit.
This should be differentiated from sequential actions, such as a frame-by-frame rendition of a dance, or the stages of creating an illustration (sketch, inking, color, etc). The latter should be how_to. This also does not include comparisons between different characters ("comparison") or different characters wearing the same outfit (often "everyone").