There's a lesser known command line tool on OS X called sips that allows image format conversion.

If all you want to do is do a basic convesion from your RAW Canon CR2 files to JPEG without any colour or esposure correction in Photoshop, then this is the tool for you!

for i in *.CR2; do sips -s format jpeg $i --out "${i%.*}.jpg"; done

Here's some images I converted earlier!

http://imgur.com/a/Ju9Xx