Note! There is currently a bug on Xperia Z / ZL where screen rotate doesn't work. I have confirmed that this will be fixed by the next firmware update of the device.
A Small App using the Sony Add-on SDK http://developer.sonymobile.com/knowledge-base/sdks/sony-add-on-sdk/ to add an icon to the small app tray that lets you toggle the "Auto-rotate screen" setting. This is good if you don't like to have autorotate on all the time, but want to temporarily go into auto rotate mode when viewing images in Album, or similiar.
Small apps extension for Sony products.
It's extra good in situations like looking at images in Xperia Album, because the status bar is not available (since Album is a full screen app), but the multitasking button (and conversely the ScreenRotate Small App) is always available!
Icon by Peter Björneskog
[ SmApEx4SoPr ] Small Apps extension for Sony products