<!DOCTYPE html> <html> <head> <title>background-size: contain; reference</title> <style type="text/css"> #outer { border: 10px solid black; width: 64px; height: 128px; } #inner { width: 64px; height: 64px; background-image: url(aqua-32x32.png); } </style> </head> <body> <div id="outer"><div id="inner"></div></div> </body> </html>