Why Do Images Default to this Value?
Design and Skin Customization
There are other crop values - none, 16:9, 4:3 (actually any ratio x:y), width, height, square, portrait... The docs are on this page:
https://www.jamroom.net/the-jamroom-network/documentation/development/1599/the-image-system
But it looks like that page needs updating, there are now more crop parameters than mentioned there.
In a template there will be a smarty jrImage_display function, you can add "crop=16:9" to that call.
I expect that scaling will be controlled by facebook's css but you could try adding the class "img_scale" or "img-responsive".
I can't help with which template for facebook though, sorry, but that's how to change it when you find it. I'm expect one of the team will be able to help further.
updated by @ultrajam: 01/03/15 05:25:20PM