There are two main types of digital image file — raster and vector. Digital photos and detailed graphics both come in raster form. Popular types of raster files include JPEG, PNG, and GIF images.
However, because their pixel number is fixed, raster images can become distorted or blurry when resized to fill a bigger or smaller space. That’s why vector images are more commonly used for illustrations and logos — vectors are made up of mathematical formulas that can scale up or down infinitely. This means that, compared to pixels, vectors don’t lose their resolution when resized.
Raw photo files, which contain uncompressed image data taken directly from a camera’s sensors, are generally converted to raster files once edited.