Sesame - thumbnail background
Enabling setting the file format by passing argument "format" to the
Thumbnail action.
For instance - 
http://local.trunk/p/100/sp/10000/thumbnail/entry_id/0_q5suunqj/width/500/height/355/format/png

Requires testing thumbnails creation.

#PS-227 #time 2 h
Merge pull request #374 from kaltura/IX-9.3.1-Thumbnail-action

Sesame - thumbnail background