#1. "RE: Going on a trip but travelling light (except for photo stuff)" In response to In response to 0
If you're shooting raw format, you're using a manufacturer's proprietary format that only certain software can use. If you want to share the images, you either need to covert the raw file to a JPEG, or shoot raw+JPEG in-camera.
AFAIK, there's no way to reduce the size of raw file.