How I do customize any sprite for any character from Fire Emblem Heroes?

[YiyaRoxie]

Well, I want to customize a sprite for any character from Fire Emblem Heroes, in my case, I want to custom the Pre-timeskip/Academy/Teenager Edelgard sprite by her swimsuit.

Which 2d painting software should I use to customize?

I think Photoshop is the best way to customize the sprites from the FEH charactes.... But I have GIMP on my PC, and I don't know it's a good idea to customize any sprite in this software?

[Izzi]

As long as the program has a pixel brush (photoshop it's a pencil brush) I don't think it matters which program you use.