For scenarios that were multiple images, having been originally posted as multiple posts (or tall posts, or multi-image/gallery posts from sites that support them), converted to animated images where each "multi-image-scenario" plays in sequence as a single post. Use a suitable frame-rate to keep each image visible; usually less than 1.

Note that most software for converting to gif will add "dithering" by default to avoid colour banding. This does not usually look good for anime-style images. Allowing colour banding generally looks better. This link has some helpful information: https://creatomate.com/blog/how-to-make-a-gif-from-a-video-using-ffmpeg

Changing "paletteuse" to "paletteuse=dither=none" in the ffmpeg command that site suggests will disable dithering.