I'm a web developer on a Mac OS X (Mountain Lion) and was wondering if there is a (free) alternative to Overlay2 - basically it's an app that lets you create a floating window with a semi-transparent image on it that you can use for direct reference - I plan on using it to match my output code to what the designer had in mind, pixel by pixel. I often just move between tabs real fast but the position isn't the same and my eyes can only be that precise.
I just don't want to have to pay $25 for such a simple functionality.