¿Criticizing java?, please, read carefully and test the game. Play for some minutes and after this, make your comments.
Don't worry, not everyone here is overly protective of Java and other technologies. Criticize whatever you want and I'll help.
The idea is pretty cool, but it took me a long time to realize what I was looking for due to it taking a while to load. A better option would probably be just to make a moving gif, as most users won't notice this functionality anyway (and won't notice if the animation is the same every time). Or you could have like 10 canned animated gifs that you choose from randomly. If you put the script into a game or something that would be different.