Adobe Photoshop
Adobe Photoshop is a raster graphics editor developed and published by ADOBE. There are many old and new versions of it and the best two are Photoshop CS6 and Photoshop CC. This program is my personal favorite because it make editing photos as simple as making a cake, it is all layers. Photoshop is very easy to sue if you are creative and can imagine, for example you can add photos and they are considered layers, just like to real photos above each other, and you can remove parts of the top layer so that some parts of the bottom layers that you want to appear will appear, and so on.