Hi

What about using systematically: * pngcrush or optipng for PNGs * jpegoptim for JPEGs

PNG optimizers may be very slow, but it's possible to get relatively quickly a good optimization, and jpegoptim is fast.

With this methods, it would be relatively easy to reduce the pictures size about 10% - 20% the image sizes. Such optimization would directly impact the bandwith usage.

Emmanuel