The background was a preset I took from Comipo, the software I used to make the whole page.
I copied that as a bitmap, and pasted it into a photoeditor as a background later.
The foreground was a picture from a machine part ( downloaded somewhere...) that I first transformed in Realdraw into a more sketchy version. Then changed it again in a photo editor ( serif photoplus X8, only 22,99 euro, as good or better than photoshop imo) to get a more graphical look.
Then made the surroundings transparant and pasted it on top of the background, made a shadow under the "flux capacitor" and lastly pasted the result back into Comipo....