I am having trouble with FF3SE?

Hi, I am new to this so I might have trouble. I decided to change the sprite of the playable characters in the game. So I decide to change Shadow's Sprite to Clyde. Then I notice that Cyan's sprite is messed up. It has random colors on his sprite. I then try to change Cyan's sprite to Dark Knight Cecil from IV. That does the same problem I had with Cyan, but it does it to Shadow/Clyde. Can someone help? Thanks.