I have created a collage in Gimp with a undefined dystopic theme. It’s created from three pictures I found on Flickr.
I started with a photo of an astronaut that I knew I wanted in the foreground of my collage.
I used mask tool to cut away the original background in the photo. For the background in my collage I used a photo of what seems to be a factory. I really liked the colors in that picture and decided to use that palette in my picture. I therefore used hue/saturation to give the astronaut an orange glow.
The last layer is created from a photo of a row of soldiers. This image had a similar color palette to the background image and even the perspective was fitting. However the picture’s width was not sufficient to fit my canvas. Instead of cropping my image I chose to copy half the soldiers with lasso tool, paste and adjust the size with scale tool. I used eraser to remove the background in this layer. To avoid an obvious repetition I swapped some of the soldiers heads. This I also did with lasso and eraser.
I had to extend the ground as well as the soldiers and this I did mainly with stamp tool, but also with rectangle select tool. I used hue/saturation constantly to make the individual layers blend in. The shadows on the soldiers and background I created simply with burn tool.
The last thing I did was adjusting details like blurring parts of the astronauts edge with blur tool and adjusting light/shadows with levels and brightness/contrast.