I have a simple website where users can post threads of images and text. However, I don't want to use emojis because they vary too much across platforms, among other issues.
My solution to this problem is to automatically convert any emoji someone types in a post to an equivalent gif image, specifically one from the SoftBank 2008 emoji set. Supposedly, the emojis would all be stored as a single GIF image on the server. I couldn't find this image, but I'm just going to assume such an image is available. (EDIT: So as @CBroe pointed out, the emojis would have to be separate GIFs, not a single GIF which contains a sheet of emojis)
So, in my server software (written in PHP), how do I convert unicode emojis in a user-generated piece of text to static GIF images?