Mail.app in 10.6.4 pastes screenshots as TIFF

Out of some behind-the-scenes frustration on the TUAW team email list, we seem to have discovered a quirk in Mac OS X 10.6.4. Using the built-in screenshot tools, you can copy a screenshot to the clipboard using Command + Control + Shift + 3 (or 4, for the crosshairs screenshot). From there you can paste into Preview or Mail or any other application which can take images from the clipboard — via The Unofficial Apple Weblog