This page shows the different variations of the GIF from an Icons8 icon pack. Feel free to resize and recolor the icon, and then download the icon in PNG format for free. Icons are available in PNG and vector.
The GIF image's main shape is a rectangle. The rectangle is taller than it is wide. The upper right corner of the rectangle has a dog-eared corner a folder over corner, like you would fold the corner of a piece of paper. In the center of the rectangle are the letters G I F to indicate the item is a GIF file.