I like it! The colors are great and the background looks nice. I really like the caption and the font you used!
I use gimp, and the only advice I could give would be to try and find higher quality renders to use. Renders are very touchy, and if you resize them they tend to lose their quality if they don't start out really nice. This is where I get most of my renders from, he does a really good job!
*EDIT* lol sry forgot to post the link to the renders xd
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it is!
Also I'd try to blur or smudge the edges of your render just enough so that it blends into your background!
Good job! I got good with gimp just by messing around with it and watching tons of tutorials and I still have a ton to learn! +rep