you have a very dirty sensor, and this is normal. Let me guess, the first image was shot at around f/16 to f/22 and the 2nd image was shot at around f/11 to f/16?. Try to shoot at largeraperture and you'll see a noticeble difference. As far as cleaning your sensor, sometimes blowing it with a blower will not eliminate the stubborn spots,hence you need to try other approaches like sending the camera to Canon for a cleaning or do-it-yourself cleaning. Just google sensor cleaning and you should find many tips. Also keep in mind that even though you never remove your lens from the camera, dust can be created by moving parts like mirrors and shutter. Another way is to use the dust deleting program that comes with your DPP software. Good luck and don't scrub![]