Creating tile sets

I’ve been learning to create tile for my 2D platformer using a new technique which is to bring 2 images into Photoshop.

To do this I searched on google for some images that I would like to blend together and then used the sequence of Ctrl+N > Enter > Ctrl+V, this brought the image into the window at its current scale. I did this for both images before selecting Image > Image size and then scaling down to 400×400 pixels.

I also learned that using  Ctrl+A to highlight the whole image and going into Edit > Define pattern will allow me to use the pattern stamp tool. This will allow my to paint my new designed pattern onto another image of plain surface.

The two tiles that I have so far are

I am unsure about the mossy light bricked tile as I used this for learning the process and I am currently thinking of where it could be used withing my game.