To anyone curious, you need to make a square image with the edges of the image being the border itself. It has to be a uniform square too.
Exactly as yumekawahanachi said!! Then the number you put in the border-image code is however many pixels tall the border part of the square image is!
Yay on Cafe Rose reaching 60 members!! It's one of my favorite weblistings ♡
yayy!! here's to many more cute members!!