The plugin in question is this: http://wordpress.org/extend/plugins/ewww-image-optimizer/
I have a bulk optimization routine that allows the user to run the optimization tools on their whole media library, or large chunks at a time. Many have had issues with it timing out, so I implemented a 'resume' function. And it works pretty well, but there are an increasing number of people who do not see any output because they have gzip enabled on their server. Thus the server can't flush any buffers, because it would break things, and the user is left sitting there wondering if anything is ever going to happen until it either finishes, or times out (I've run it for as long as 2 hours before, so this isn't a fun scenario).
I've tried turning off gzip, but since my code gets executed after portions of the page have already been built, this doesn't work. If there is a way to turn off gzip before wordpress even starts building/loading the page, that would possibly make this a moot issue.
So... am I missing something, is there a way to make this work? If the ajax doesn't work, is there a way to turn off gzip before wordpress starts loading the page? Or am I best served just going back to the way things were?