You can add your Avatar to the video area by changing your avatar in your profile. Go to the top right corner of this webpage where it says 'welcome' and click on it. Select 'my account'. Scroll down to 'photo' and place a photo there. The Photo change to the game will be delayed (about 15minutes for me) so be patient.
The only drawback to this is that it will remain constant across any games you play. You could change the image before entering a game although I imagine that would become tedious.
Donald W. said,
I don't want to change my account avatar to be my character avatar. As I don't want to have to switch it for every game i play.
Speaking of this, it would be nice if the current behaviour and issues of Roll20 avatars (user profile pics) could give rise to some implementation of character portraits beyond the current way: they appearing in the character sheets at the Journal.
For instance --this is a modified screenshot for showing what I mean:
It's just a suggestion, but with this approach, it could be possible to click one of these portraits for opening the corresponding character sheet at the Journal, too.
In this way there would be an option for having the character portraits at view all the time --enhancing the focus into your character, adding to role playing--, in the same way people using WebCams have video feeds displayed regardless the Roll20 page selected.
As the above screenshot shows, currently I can get a horizontal file of character portraits in Roll20 if my players switch their Roll20 user profile images or "avatars" to suitable portraits of their characters for a given game, but as Gauss is pointing, this is a substandard solution: changing the user profile picture means extra work, requires additional time, interferes with the forums' activity which already is using user profile pictures/avatars . . .
Besides, it requires for participants to disable WebCams because this use of profile pictures as character portraits is not --to my understanding-- actually intended nor truly supported by the Roll20 app: since you can't have both, you need to chose WebCam or profile picture.