#8 Combining pictures

Imagine you have two pictures and want to make them into one proper picture. You have drawn two layers of one picture using pencil, got both to computer and now you need to put the layers on top of each other so that it all works as intended. On the picture below is an example of what I mean, I have a picture of a hand holding a pencil (top layer) and a drawn knight (bottom layer) and I want the image that combines both.

It took me some googling and experimenting to find out that what I need is to let the picture with the knight as it is and cut the hand from the first picture. But! Cutting the hand by hand (ha, humour) would be madness. 

There is a nice tool in Gimp software, that can automatically select foreground, which is apparently what I want. If I understood the stuff I found by random googling well, it works by recognizing colours (or something like that) and separating the background from the foreground based on the colours (or something like that). On my picture (that you can see above) colours are not really involved, there is just line and the rest. Which can be easily fixed by colouring the parts of the picture I want to delete with some absurd colour. Like green.

   

And then just use the foreground select tool, which is described here. This selects the hand. Then all I did was inverse the selection (Ctrl+I) and delete everything selected (Ctrl+X). It all worked surprisingly well and quickly, but it took me a while to find out what do I want and how do I do it. So maybe someone finds this helpful.

After deleting the unnecessary bits, you can just put this picture with a hand on any other picture. And make it work as one picture.