Using literally to mean figuratively is just fine. They're being ironic, or hyperbolic. Then and than mean different things. To a lay person, a gif is a short,

Using literally to mean figuratively is just fine. They're being ironic, or hyperbolic. Then and than mean different things. To a lay person, a gif is a short, looping, soundless video. I'm not sure what is being lost by not distinguishing between this and a short mp4 file with no sound on loop.