I try to keep it less than 2 MB. While catbox allows us upto 200 MB, it's better to keep it smaller :)
So I'm using Voyager and I've had trouble getting gifs over 900k to post. Are you posting the image or the link and through what client?
I'm using alexandrite frontend because it consumes less data, easier to navigate. As I said, I'll try to keep it smaller.