I hope this isn't an idiot question ...
I have CS5 on Windows 7. When I download photos from my Canon camera, their size is 48x72 inches @ 72 ppi. Previously, when I used the crop tool to adjust the image to the size I wanted, the resolution would rise accordingly, to 300 ppi or more. Now when I crop the photo, the ppi stays at 72. I haven't a clue as to why this is, or where to check to fix it. Can you help? Thanks!

I have CS5 on Windows 7. When I download photos from my Canon camera, their size is 48x72 inches @ 72 ppi. Previously, when I used the crop tool to adjust the image to the size I wanted, the resolution would rise accordingly, to 300 ppi or more. Now when I crop the photo, the ppi stays at 72. I haven't a clue as to why this is, or where to check to fix it. Can you help? Thanks!