GIMP 2.8 Python Plug-in.
This plug-in scales the contents of the layer (or layer group) to image size.
1. Close GIMP if it is open.
2. Extract "scale-layer-to-image-size.py" from zip archive to the ".../.gimp-2.8/plug-ins" directory.
3. Run GIMP. The plug-in should appear under the menu: "Layer > Scale Layer to Image Size". Don't forget to make the plug-in executable.
This plug-in requires Python!