My pictures are only 72 DPI. How can I change the resolution to higher quality?

Set the camera for the highest megapixels and picture quality to the highest level.

reset your camers settings.

Your camera cannont shoot at either 72 dpi or 300 dpi. It shoots at whatever resolution you have it set for. Dpi (dots per inch) is a print specification, denoting how large (or small) your pictures are printed.

The DSC-W100's highest resolution is 3264x2448. Printed at 72 dpi, it can generate a print bigger than 40x30 inches, albeit a bit grainy. Printed at 300 dpi, you can generate 10x8 inch prints.

Again, dpi is a measure of how you print pictures. It has no bearing on how you capture images with your camera.

A couple of things - I don't think you mean 500 megapixels (that is a lot!) but I assume you mean you expected a high resolution image. You may have it! The dpi setting is largely irrelevant (for photographers) as it simply relates number of pixels to a (notional) print size. Thus an image that is 3000 pixels wide (say) would print out to 10 inches at 300 dpi (3000/300) or 40 inches (approx) at 72 dpi (3000/72). the image has the same information /resolution - it's just "spread" further on the larger print. You can easily change the nominal dpi in e.g. Photshop Elements but it won't affect your image quality.
If however you are getting low resolution images when setting the camera differently that's something different. I would need extra info to help there but pssibly check if the camera was set to RAW and maybe you were looking at the (small) JPEG usually saved with it?

Sony H1 takes photos at 72 dpi by default. But the picture quality will be good. if you want to convert it to 300dpi open the picture in adobe Photoshop and select image size and change resolution to 300 dpi. but the file size will be very high to up load. if you want to reduce the file size select the image size in adobe photoshop and reduce it according to your requirement. if my solution proves good please rate it. Regards.

You can use a photo editing software on your computer to change the dpi, 

dpi has todo with printing and scaning dpi has no real change in the quality of your camera pictures
look at this page

http://www.rideau-info.com/photos/mythdpi.html

using the RAW setting will give a higher quality photo, the other formats compress to jpeg causing you to loose some of the original photo information. the ZoomBrowser EX program allows you to edit the RAW image, I recommend getting the large prints done at Kinkos or some place like that. I've gotten poster size prints done that look very clear. Use a tripod to combat camera shake, it is very apperent at that size of print. Also a low ISO to help reduce noise.

Many cameras will take pictures at only 72 dpi. Changing the resolution causes the camera to change the size of the picture in terms of pixel dimension (ie 800x600 vs 640x480) but always at 72 dots per inch. A photo editing program like Photoshop can change the resolution to whatever you need.

menu- camera set up- picture quality- try to locate picture size using menu button switch. RAW file is the best but it eats too much memory.

What you are seeing is the difference between "pixel count resolution" and "embedded resolution". So in your example 2272*1704 is the actual pixel count resolution as recorded by the camera & 72 is the embedded resolution that tells the software (in this case photoshop) what the intended use of the picture will be. 72 ppi is the default for web pictures. You can change this in photoshop by going to the "Image" tab & select image size. The window that opens will show you the pixel dimensions i.e. pixel count resolution and the document size & resolution 72. You just change it to 300 for printing. You can change the default to 300 by going "edit", "preferences", "units & rulers" and setting the values for "new document preset resolutions". This is a complex subject, I recommend looking at the following web page: http://www.fotofinish.com/resources/centers/photo/resolution.htm