Not making a backup of the original image
Whenever you download images from a memory card, it’s essential to make a backup, either to an external hard drive or on a cloud storage service. This reduces the risk of images being lost if your computer breaks down. It’s also vital to do so before you open an image in your photo editing software.
Editing an original image and then saving it means you can’t fix major mistakes or return to a picture and start a fresh edit if you’re unhappy with how things have turned out. This is especially true if you resize an image, only to find a client has a different vision of what the final edit should look like.