Download

using Unreal Engine as a still renderer

Is It possible to setup a scene and have it render out as jpg or avi?

Yes. You can capture a movie or image sequence with Matinee, and you can take screenshots with the screenshot tool or by using highresshot console command.

Also in 4.5, EXR format support was added, which will help a bunch for stills. https://www.unrealengine.com/blog/unreal-engine-45-released