Still pretty buggy Rated 3 out of 5 stars

Unusable for me but I'm giving it a three because when it works it's really helpful. Not working in ff 15.0.1, firebug 1.10.3, OSX 10.8.1. On installation, the overlay panel is visible and I successfully added an overlay (which was successfully added to the proper folder in the extension's file tree) but the checkbox to use the overlay is uncheckable. On restart the overlay image (and any added manually through the filesystem) are not listed and the "Add Overlay" button does not appear.

Poor man's pixel perfect from the console (edit the image path as necessary, uses jquery):

markup = '<div class="db"></div>';
$('body').append(markup);
$('.db').css({ 'z-index' : 999, width: '100%', height : '900px', opacity : '.5', background: '#fff url(/gfx/overlay.png) center top no-repeat', position: 'absolute', left: 0, top: 0})

This review is for a previous version of the add-on (1.7.1.1-signed). 

i wish i had thought of it Rated 5 out of 5 stars

I've only used this for about 5 minutes, but it is obvious already this is the best new extension idea (albeit an extension to an extension) I've seen in a couple months. No more alt-tabbing from photoshop to firefox. Appears pretty solid out of the gate too.

This review is for a previous version of the add-on (0.5.4).