Why do I need to add EXEs to my bin?

RequestReduce includes optipng.exe to losslessly optimize the compression of the png files that RequestReduce generates containing all of your sprited background images. I recommend you add this to your bin directory along with the RequestReduce dll. This optimization process has no visible impact on the image and can significantly reduce the size of the background images which then translates to faster performance of your site. Because RequestReduce performs its optimizations in a background thread and these optimizations are serialized (done one at a time), performing them by invoking a shell does not produce any potential ill effects.

If desired, you can remove this EXE from your bin. RequestReduce will continue to process your Responses but will simply not invoke optipng.exe. You can also adjust the RequestReduce Configuration options to explicitly tell RequestReduce not to perform image optimizations.