bobbyfowler, you'd need to give out more information :-
pixels per inch - what do you mean by this - pixels on a printed photo, the resolution of the captured photo jpeg?
Assuming you mean pixels printed, 72 pixels per inch in a 6x4 photo is 432x288. which is quite small for a photo jpeg (assuming it's not a cropped extract of the original). Rather than looking at the quality setting, check to see if there's a picture size option in your camera. If that all checks out, check the options you have for extracting the photo files from your camera e.g. raw, jpeg etc. Then check how you're processing them, eg. what software is used to print etc. Failing that, talk to the shop who sold you the camera and get them to demonstrate how it works!