Does the job

I had many hundreds of photos that would consume far too much space in my photo libraries. This utility provides a simple way to apply selected parameters of size reduction to all the photos at once … store separately, or over-write the old … preserves creation/modification dates if desired. For simple non-studio quality (view on-screen without a plan to print large formats), this tool is superb; photos typically reduce from 6MB to 375KB with no difference in size or viewable quality. Using magnification on finely-shaded areas, some pixelation comes-in, as you have to expect - but for normal viewing, this tool fills the bill. Just reduce less, or don’t compress if you think you’ll want to posterize your photo one day.

I use it with OS X 10.9.1, MacBook Pro with 8GB RAM and performance is quick and flawless.

1 DoDad about PhotoResize Pro