Open a GIF animation in Ristretto (e.g. this http://jdem.cz/bun33). Each time, when the animation is about to start again, the little icon of an arrow is shown instead of one GIF frame.
I noticed that the interruptions while looping often contain parts of other pictures/animations in the same folder. Also, there's often just a gray flash during looping
I can't reproduce this in master. Closing this ticket. After 2 re-implementations of the image-viewer widget, this bug probably disappeared.
No longer exists :)