When using a Sprite from a characters folder for it's portrait

Ok my question is:
Are there any other reasons why a chars Sprite won't show corectly as their portrait other than.........

1. If the sprite is not indexed correctly
2. If the sprite is not saved to a workable pallete
3. If another Sprite has 9000,1
4. (Sometimes) during saving it ask to organize your sprite folder. (Sometimes I just exit and let it save and it works)

Am I missing any other reasons why my sprites may not be showing up/or show up distorted.

In ex. Rogue csp by acey has a Sprite as a portrait and I tried to replace it with a new one from her def but I've tried the first three and it won't appear (the fourth option doesn't come up so that can't be the problem) also the sprite I saved has a brown jacket and when it add it back in there's only one pal like that I can save in the pal editor on the right but it still won't show.

From experience and as far as i know, there's pretty much nothing else to write home about, save for things like the size of your portrait, normally it's 120x140 pixels, but there are unique situations like full game projects that have other size standards.
Also, you should always have a transparent color in the portrait's palette unless you want some kind of background for it.

@mistah Jorge thanks I didn't think there were anything else. Thank you for responding.