AlphaCapture for Mac

From Balance Software:

AlphaCapture is a full-featured, professional screen capture utility for MacOS X. Its name is derived from its unique ability to save an image of the screen that preserves the transparency of on-screen windows (shadows, translucent areas, etc.). This information is stored (in image formats that support transparency) as an "alpha-channel".

A web designer, technical writer, or any person who needs to take screenshots can now superimpose captured images on a background of their choosing and transparent or translucent window areas will allow the background to show through in an expected and visually pleasing manner.

AlphaCapture supports numerous features that are essential to a professional screen capture tool; examples include:

• Hiding/Toggling Desktop icons during capture.
• Transparent Desktop capture.
• Photoshop®-like "Trim" function to remove transparent edges.
• Optional "checkered-background" during transparent marquee capture.
• Hiding/Toggling mouse cursor during capture.
• Rectangular (marquee) or full-screen capture modes.
• User-assignable hot keys for invoking screen capture.
• User-assignable pause before capture.
• Output to multiple image formats (or to the clipboard).
• User-specifiable destination folder for captures.
• On-the-fly changing of options during marquee capture.
• User may abort a marquee capture.
• Plus many more features!