Sometimes you just feel like Photoshopping your teacher's head onto Mario's body. For those times here is an easy guide so that your teacher can be riding Yoshi in no time.
Step 1: Opening the photo & Erasing the background
Once you've opened Photoshop, go to File, Open and find your file on the computer, once you've done that click open. Now that you have your photo open, let's start by getting rid of the white background. Use the magic wand and click on the white background, once the background is selected, hit the delete button on your keyboard. Now that you deleted the background, open the picture of the person you wish to photoshop onto Yoshi.