If you're having an issue with your (straight out of the camera) digital images, it may be one of the following things:
Dust on your sensor... If you see little specks on your images, probably in the same areas, it's most likely dust. This is very common, and pretty easy to fix. There's a few options to clean your sensor including: by the cameras "sensor clean" in the menu, by store bought kits, or by a professional repair shop. This will only occur on a digital SLR, happens often, and is mostly preventable. For tips to keep this mess out of your life, refer HERE and HERE.
This is an example image from a bad CCD. This can happen in both point & shoot digital cameras and digital SLRs. This is especially a common issue in many of the older p&s. This is an extreme case of bad CCD, but they sometimes go out gradually and you may have your actual taken image with some minor lines or discoloration through it. This is not an easy problem to fix, and is not an issue for home repair. If you have this problem, you will need to send that camera out to a repair shop, or in some cases may be under warranty through the distributor.