I've noticed that, and tried to fix it by saving both a image on my computer and uploading one from the URL to the imageshack hosting that the userbars are on - but it didn't work. I just found (about 20 minutes ago) another offsite userbar animator, and I'll test it first.
And the idea of the userbar is pretty popular - they have a bad forum board
but there are at least 1500+ userbars (I mean way under estimated number). Other people can make these for more people, and overall it's flying. I've really never noticed a exact userbar shift that is the same. So, it's pretty customisable, and it's popular with some. So it'll work for now at least