Test page was experimenting with using a series of PNGs for an animated spinner cursor. This was to get full RGBA (I still bemoan the death of MNG/JNG) and because Gecko at least does not support gif/ani cursor animation, even without the RGBA. Under Gecko, the animation spins smoothly, updating every 100ms with no noticeable consumption of CPU. Under Webkit, the image only shifts on mouse move, so you can only observe the animation by continuously moving the mouse. I will upload a data URI variant.
Created attachment 26371 [details] Demo
*** This bug has been marked as a duplicate of 14344 ***