All translators, who have been around for some time, have a roster of tools to make their life easier, and improve quality of their work. (This may not be obvious, but the former is a direct precursor of the latter.)
The easiest examples are Apsic Xbench, and Apsic Comparator. I won't be telling you, how great, and useful they are, this is not the subject of this post, but if you don't have them, go get them here right now.
Another thing worth mentioning is search/replace tools, which are essential when you revise a project that contains hundreds of files. My choice here is Text Workbench, which supports binary Office files unlike the competitors.
I can go on, but that's not our subject again. To the point:
Recently I have learnt about the tool, which seems to be just as useful as Xbench for certain kinds of jobs, more specifically liguistic QA of localized web sites, and applications via screenshots, or browser. The idea is very simple — the tool consists of two panes. You open a source screenshot or web page on one side, and a localized target one on the other. Then you compare them, and go to the next pair with a click of a single button.
The tool is opensource, and thus it is flighty, and unstable, but it's still much better than two browser, or image viewer windows.
You can also download the compiled file here
Can't wait to try it for "big" web application testing. Great addition for my roster.