Background HQ, or BGHQ for short, is a website established in 2004 for the purpose of providing sprite backgrounds for use in the creation of sprite comics and sprite-based video games.
Older video game systems such as the Super Nintendo, the Sega Genesis, and even the Gameboy Advanced, used distinctly different, 2D graphical layers to display games. By using programs that can emulate these systems, each of these graphical layers can be removed and a snapshot taken of their contents. The images of Mario from Super Mario World can be placed on different backgrounds, put in different poses, and then special effects and text can be added. The result of this is what is called a sprite comic.
BGHQ is focused solely on backgrounds for these sprite comics. If you're looking for where you can find character sprites, try looking at sites like The Spriter's Resource or Sprites INC.
BGHQ is no longer updated, but its original archive is still available for browsing and use.
For more information about the site, see our About page.