Polish dweet gif watermarks

Currently watermarks looks like this:

There's been talk about changing them; either in minor ways, like moving them back to the top, adding a white bar at the bottom so they don't overlap the dweet (which would allow cropping for better or worse), or bigger features like various options to remove them for some users (maybe the author himself).

Making this issue to hear what the community has to say, and as a place for comments as more people start to actually use the feature.

Start by reviewing the current dweet GIF watermark implementation and the example linked in the issue. Clarify whether the goal is repositioning, adding a bottom bar, cropping, or user-specific removal; done means one agreed watermark behavior is implemented and visually checked.

Written by the indexing model from the issue text.