Pixel Dispersion Effect (Photoshop Practise)

First I found an image I wanted to pixelate, I then created a new layer and made it larger and stretched the image in the direction I wanted the pixelation to go in, after messing around with the size of the image i then selected a brush, I chose square to have that spaced pixels, then I chose the colour white on the first layer (small image), went around the edge of my image to give it a pixelated looking edge, then I selected my second copy (larger image) and then I changed the cokour of the brush tool and used it on the larger image to make it looking pixelated overall.