Look at the dimensions. e.g. if the pixels are 1000×400, then you can’t print anything over a 4″x4″ photo. You can download free software like irfanview, double click the image and press “I” to view image size, camera make, etc. The pics you have on line are NOT enlargeable. You need the original from your camera, typically 3-4x bigger than on-screen. Also, the more the megapixels in your camera, the better the chances of being able to enlarge something out of the original file.