With iPhoto 9.4.3, Apple has enhanced the consumer-level photo management app’s Photo Stream support and fixed a handful of bugs. Photos can now be deleted from My Photo Stream by dragging them to the Trash, you can use File > Export to export photos from Photo Stream, and raw images manually imported from My Photo Stream are now editable. On the bug-squashing side of the equation, one fix prevents manually rotated photos from appearing unrotated when shared to Photo Stream, another addresses a crash when syncing to Facebook, a third prevents calendar text from appearing at the wrong size and resulting in order cancellation, and the final one fixes a problem that could cause books to have an incorrect number of pages after rearranging two-page spreads. ($14.99 new from the Mac App Store, free update through the Mac App Store or Software Update, 730.91 MB direct download via Apple’s support page)
Go Back and Forth Fast in Preview
If you're reading a PDF in Apple's Preview software, and you follow a bookmark or an internal link to move around within the PDF, you can quickly return to where you were by pressing the keyboard shortcut Command-[ (that's Command-Left Bracket). Or, you can choose Go > Back.
The command works iteratively, so you can go back to just the previously viewed page or if you issue the command again, to the page before that, and so on. There's also an equivalent Go > Forward (Command-]).