**System Information**
Windows 7, Nvidia 2x660GT
**Blender Version**
Broken: Blender 2.7 (release candidate)
Worked: Blender 2.68/9
**Short description of error**
Adding new nodes to the compositor will not effect the output image (F11). This forces you you to re-render the image in order to save it.
**Exact steps for others to reproduce the error**
(This is a fairly big bug, so my apologies if it's already been reported. I just couldn't find it.)
1. Render an image
2. Go to the compositor and add some new nodes (any will work).
3. Press F11 and only the original image will show. The new nodes aren't included in the composite. This forces you to re-render the image if you want to save it.
Note that you can preview the changes fine by using the preview node, but you can't save it as it won't show in the output image until re-rendered.