Select the
Background and try to move the
Opacity slider. You will notice that this is not possible. Try it now with
Raster 1 and you will notice that the background starts to shine through on Pic.2. I've set it to 38 percent but you can of course set it to whatever you think looks best.
Now once you've done that all we have to do is merge down the layer onto the background. To do this go to
Layers at the top bar and go to
Merge on the roll-down menu, select
Merge All (Flatten) (
Pic.7) and you're done. Also note that you could select
Merge Visible. This is easy if you are working with more layers and were mixing up just a few of them. Once you are satisfied with the result you could decide to merge the visible layers down to one layer.
These are the basics you need to know about
Layers to be able to mix two pictures together. Look at the result down below. First the two original images and then the mixed one. That's all. We're done.