How do I find out what format my photos are in?

To find out the format of your photos, you can check the file extension in the file name, such as .jpg, .png, or .gif. Alternatively, you can right-click on the photo file, select "Properties" on Windows or "Get Info" on Mac, and look for the file type or format listed in the details. Additionally, you can open the photo in an image viewer or editing software, which typically displays the format in the file information or properties section.