It looks to me like the image you're using is already an animated gif of a bug, then you're applying script to it to move it around as well, so it's no wonder that it might appear to move backwards, etc. You're moving an image of something moving. I think the intention of the script that you're using is that the image is not an animated gif.
Note, the reason it looks smooth in IE is because the script is throwing an error in IE which is preventing it from moving the image around the page. Therefore, all you're seeing in IE is the regular animated gif in a fixed location.
Hi+ Thank you for the quick response! I found the script & just changed from the bug they were using to the bedbug. But, I did make it an animated gif...I will post a thread in the other forum for assistance with that. Thank you for clarifying the issue for me! I really appreciate it!