Generally it is best to try and do as little cropping as possible. Especially with APS-C sensors that are not the same with regards to quality as an APS-H (now discontinued) or full frame sensors. One of the reasons is that the manufacturers try to cram more and more pixels into a small area, which creates problems with pixel size and dynamic range etc. etc... If you crop an APS-C image in half and especially if your original image was of a mediocre quality, the half-size image will look very bad.
The reason jpegs may look bad is also how your friend sets the camera up. After all, the camera processes the image internally, rather than you or her later on a computer.
Get her to read the manual and understand what each preset option can do. Contrast, saturation, etc... The reason most people who are pretty serious shoot RAW files is that they have far more control over final image quality. Compare the file sizes. Your RAW should be nearly three times the size (in megabytes) of your highest, finest, jpeg. That means that much more data to work with. But digital is not the panacea for poor exposure skills. You may or may not have heard things like: Ah, if I get it right in camera I can fix it in Photoshop later. This is the biggest garbage statement one can say in my opinion. To get the best image quality, one must learn how to expose in digital world, that is; use the histogram on the camera and understand how the image is recorded. The proper exposure technique will ensure the recording of the maximum number of high-quality pixels and also minimize or totally eliminate dreaded digital noise. The below link is to a blog entry I wrote some time ago about digital exposure and what I do to minimize noise. While the post is about using high ISOs and noise in relation to that, the crux is still relevant to all ISO values.
A MATTER OF LIGHT ยป Minimizing noise when shooting at high ISOs.
In essence, I always shoot RAW and convert to jpeg before I post them on my web gallery or other digital media. I even send large, fine, jpegs to clients rather than bulky TIFF or PSD (Photoshop Document) files.
Digital Photo Professional should've been included with your friend's camera on a CD. If not, she can download it from the net. Just google DPP download or something like that and bingo.

