Zukan's Recent Posts
Still works in Mavericks, does exactly what it's supposed to do. VERY lightweight and non-taxing on the system. A little hard to set up and understand though, and sometimes the app will randomly quit, but it happens so rarely that it's barely an issue.
I just optimized a folder full of large jpegs around 4GB, down to 600mb without almost any visible compression artefacting. It was very quick too, I am quite baffled at the results of this app.