Using the „Scale to Fit“ option in the Backgrounds panel can result in images that don’t look as good as they could, and consumes a few additional system resources.
To speed things up, rescale your original images to a more managable size, using „Massive Picture Converter“ or The Awesome Resizer .
Both of these apps support batch conversions so you can mass-convert a gallery of artwork for use as backgrounds on different Workspaces, or for use with Cycler.
You can get some really nice background artwork from Propaganda, Digital Blasphemy, or resources.themes.org, or for more BeOS Specific Images, the BeNews Media Center.