Improvements on saving composites needed

Hi,

Although Blender has a pretty decent compositor, some of the workflow is a bit cumbersome. Why do we need to hop back and forth between the compositor view and the UV/Image Editor, just to load the Viewer node and save an image? Wouldn't it be far more logical to have additional functionality on the File Output node?

On the File Output node here's already the ability to change the default file format if needed, so a basic render button would skip the roundtrip to the UV/Image Editor all together. And makes it less confusing as a workflow.

Also, add the option to -also- be able to deviate from the default Frame Start/Ends, so one can render different frame sequences as well.

Here's a quick mockup, I'm pretty sure some smart Blender peeps can come up with additions or tweaks...