i made mine in procreate, i just took an existing image i already had and manually added a rainbow background animation by editing the background color in each frame. i do think theres button makers out there where you can just import your image and it will do the rest tho!
There's sadgrl's button maker which is a good start I think https://sadgrlonline.github.io/88x31-button-maker/ And if you want to play around with pixel art a bit more you should check out https://www.pixilart.com/
Ahhhhhh thank you so much. By the way, I adore your art!
awww, thank you so much!! :-)