Hmm, okay... I think, generally it looks okay ^^
The extraction is fine and everything is done with good placement.. however, some things...
- you have blurred the background way too much...most of it are so blurred that the scan kinda look outta place...
what's more, you cannot really see the grass in front, so it seems as if the focal point is only on the scan, which
looks kinda weird.. you may want to lessen the blur in the background elements, especially the trees near her :D
- I think the lighting is not good... >.< the scan is waaaaaay too bright for the wall.. since even the grasses
cannot be seen, it is imposibble for the scan to be that bright... it's either you darken the scan, or make the
grasses and leaves more viewable (lighter colors)..the easy way would be darkening the scan, you may try to desaturate
the scan a bit and make it more shadow-y so that it matches the darkness of the wall (but even then, the sky doesnt look
that dark, so maybe you should make everything else a bit lighter in color and therefore brighter :))
If you wanna add something, I suggest you put text on it :D no moon/stars please, that is way too cliche, and I think
the background is already nice enough as simple as it is now ;D
Hope that helps ^^