image files. there should only be three. .gif .png and .jpg! PNGs give you no background, GIFS for animations without sound and JPGs are for reducing the hell out of images. Instead, we have all the extras like; WEBP (hate), BMP, EPS, ICNS, ICO, ODD, PS, PSD, TIFF (tiffany!?), and XPS. Theres also vectors like .SVG files which I'm not hating but not liking. Something like a PDF wouldn't be considered as an image file.