1. The accepted maximum resolution for signatures is 540x150.
2. The animation is twitchy. If you want to fix this, put all the frames of the animation into the same file, make the bottom layer solid, make the next layer up 50% opacity, and the rest transparent. Align the static part of the image, in this case blackboard, across the two visible layers. Once you have them lined up, make the 50% fully opaque and then make the next layer 50%. Do this until all of the layers have the blackboard in the same place across all the layers. Then crop and resize as desired.
3. Too bloody fast. Even without the twitchy animation, the image needs to be slowed down. 500ms, perhaps even 1000ms for each frame. Until then, I'm gonna just go ahead and kill the image with Ad-Blocker, because sitting here watching it while I typed this has made my brain hurt.