GIF is a good format for any simple image with few colors. It is also the only image format that supports animation of a series of files. It is supported well on all browsers, including legacy versions of Internet Explorer. When creating new content online today, most people choose PNG because of it’s better transparency, alpha-channel support, indexed color and smaller file size. GIF is still an absolutely fine, safe choice. if that’s what your editing software outputs and 256 colors is enough, go ahead and use GIF.