.gifs with Layers Smaller Than Images Are Misaligned

User AgentString: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:40.0) Gecko/20100101 Firefox/40.0

This trial has sprites appear in the top-left corner for a split-second before being properly positioned, due to its use of 256x192 images, but optimized layers that are smaller.

Glitch may not be fixable without filing a bug report with Mozilla. May be Mac-specific.