Depozyt and other 65,000 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
This appears to be a circle with a 5 in the center of it. There's a square underneath the circle that's missing its top line. There is an arrow that is pointing from the bottom of the circle to the bottom of the square.