JPG, PNG, and WEBP are all supported, which covers essentially anything a phone or camera produces and anything you save from a website.
Resolution matters more than format. A clear, well-lit photo at a reasonable size gives the model detail to work with, while a small screenshot forces it to invent texture that was never there. When saving a product image from a shop, open it in a new tab to get the full-size version rather than right-clicking the thumbnail in a listing grid.
For photos of yourself, the frame should include the area where the clothing will be worn. Full body is best for anything below the waist or where hem position matters, and at minimum you want down to mid-thigh so proportions stay correct.
Screenshots work but are usually the weakest option, because they capture the image at whatever size it was displayed rather than its true resolution. If you have the choice, save the original.