Patrick's answer was the first that I've seen that broke my logjam of frustration in not finding this answer anywhere. It sounds like you were using the NAV1 route, where 4x6 is the default choice. As I have dozens of photos to scan, doing this one by one would be painstakingly slow as well as off-putting, which is why I haven't done it for years. The existing documentation didn't cover, ironically, navigation.
To scan a letter sized item with your PIXMA MP560 and save it to your USB drive, please follow these steps:
1. Turn your PIXMA MP560 on.
2. Press the HOME button.
3. Rotate the wheel around the OK button with your fingertip until you reach Scan, then press OK.
4. Insert the USB flash drive into the Direct Print Port or a memory card into the Card Slot.
5. Rotate the wheel around the OK button with your fingertip until the medium you're using appears: USB flash drive or Memory card, then press the OK button. Press the OK button a second time.
6. The default or the last settings you used appear. To change these, use the Down arrow to get to the size, press OK. Navigate to Letter (or whatever size you want, A4, 4x6, or 5x7) and press the OK button.
7. The default is 300 dpi. If you want something different, e.g 150 dpi for lesser/Low and 600 dpi for the best/High on this scanner, use the Down arrow to get to the dpi line, press OK. On the next screen navigate to the dpi that you want, then press enter again.
8. The default type is PDF. For a photo, you'd want to use the down arrow to highlight that, press OK, then on the next screen use the down arrow to highlight JPEG, then press OK again.
9. Next should be highlighted in gold (it's difficult to tell) at the top of the screen, press OK. Press OK again to continue.
10. As shown on your printer's small screen, load the original on the Platen Glass following the instruction on the LCD (facing the printer with the buttons on your right and the platen on your left, the upper left corner of the platen is the top left of what you're scanning).
11. For color scanning, press the (green) Color button, for black and white scanning, press the (white) Black button for black & white scanning.
12. An image will appear on your MP560's small screen. If OK, press OK. For color scanning, this takes about 30 seconds.
13. The settings screen will show again. If you have more to scan, change them if you wish, otherwise, since Next is highlighted, press OK. On the next screen, press OK again. If you don't, I press the ON button to turn it off and disengage the USB drive. In a document scan, I get a Continue or End button, this way I did not. Keep in mind, though, that image files can get quite large. For me, 1 sheet of six small pictures that, all together, are 8.5 x 11, was 4.3 MB.
14. On a USB drive (and probably a memory card, which I haven't tried), there's a Canon folder with a Document subfolder, where your scanned PDFs are saved, and an Image subfolder, where your JPEGs are stored.
15. My guess is that if your next scan is a document, you will have to go through a similar process to change the settings so as to be appropriate for a document (Document, PDF, probably 300 dpi, perhaps black and white).
