making a set of textures that can be placed wherever

https://preview.redd.it/zgf2ky30jbbf1.png?width=1610&format=png&auto=webp&s=7d71d0fd3b82dde68b139736d8bcaa50024bc0d1

I have a sword I'm making and it has a large amount of panels along the blade and I want to be able to have a couple textures for every letter in the alphabet and each one is currently using the same texture. I'm attempting to save the texture for the panels with the letters but then it does not save and I cannot place it again.