Image batch conversion

Hi
New to macs and looking for software (other than Photoshop or Elements) that will do some batch processing on a large folder of files.

What will be needed is a conversion from RAW (.ARW) to JPG and
a 50% reduction in image size and possibly a file rename.
Any of you folks use such a thing and can recomend something?

I assume iphoto won't do this nor Aperture...

Thanks for any help

GraphicConverter can use to do a batch conversion or .RAW to .jpg.

There is an app that will batch rename files, but I don't remember what it is at this time. I don't know about your last item of resizing.