The Coder's Handbook
Sticking to one image format will make your life a lot easier, since you won't need to keep checking file extensions.
This is an image of a capybara, also known as the
Coconut Doggo, the most noble of all creatures.
Be careful when resizing images. It can caused images to become blurry or stretched - and tends to take a lot of runtime.
Chapter 15 - Images
Shiffman 10.1 - Intro to Images
Shiffman 10.5 - Image Procesing with Pixels
Shiffman 10.6 - Pixel Neighbors
Shiffman 10.7 - Painting with Pixels