Sometimes when you are resizing or transforming an image in the full version of Photoshop, it would be helpful to see how it's going to look so you can compare it to the original. Pressing Alt Ctrl T (Mac: Opt Cmd T) on your keyboard opens the transform controls but when you perform the transformation, the software creates a copy of your image instead of altering the original.
You can toggle back and forth between the original and transformed image by clicking the layer visibility icon which looks like an eyeball on the left side of the layers in the Layers panel. You can even hide one of the images, but keep it available in your file so that you can make a decision later if you like.
This is a nondestructive way to use transform controls to resize or otherwise alter a layer.