VTM version 10.0.0.0 is able to produce 2 types of animated thumbnail sheets - WebM and WebP.
You can create up to 2 minutes of animated thumbnail sheets and combine animations from several part of your video within a single thumbnail sheet.
Framerate is up to 60 FPS.
Differences between formats are shown in the table below:
WebM demonstration page
WebP demonstration page
And here are some examples of WebM animations (4 seconds each).
Previews are scaled to 1000px width by forum rules. You can zoom to native size or full screen using video Controls (hover the mouse over the video to view Controls).
How to embed WebM to forums (phpBB, vBulletin, IPB, Simple Machines, MyBB, ...)