Step 1: Upload Picture and resize it to your liking. (I used a PNG of Taemin from SHINee. PNG: Picture with no background )

Step 2: Duplicate this layer. ( I have a huge black box around stuff on the picture that I want you to look at and it just inverts the color of everything :P) I zoomed up on the layers so you can see I duplicated it.

Step 3: Hide the top layer and click on the bottom layer. Next you  go to  Colours and click on colorize.
Now move the Hue and Saturation all the way across to the right.

This will give you an image sort of like this.

Step 4: Unhide the hiden layer and repeat the last steps except only move the saturation 

You will now have something like this

Step 5: Lower the opacity of the blue taemin layer to 50%
 

You will have something like this:

And the last step is to slightly move the Blue layer left or Right. Up or Down and you will have something like this. and also merge the blue layer with the red layer.

I made a poster using this and this is how it turned out.