Send your file to the GIMP, then start G’MIC (install gimp-gmic for that), choose in section Decorations (or something like that) the borders you want. In other words, what you are asking for does already exist.
Send your file to the GIMP, then start G’MIC (install gimp-gmic for that), choose in section Decorations (or something like that) the borders you want. In other words, what you are asking for does already exist.