Paper size of scanned images from feeder is always wrong
With page size set to the default value (Automatic) in Preferences -> Scanning, here is my poor result when scanning a standard letter-sized paper:
wrong-automatic-paper-size.pdf
Note there is a blank space at the bottom of the scanned image, below where I wrote "This is the bottom of my paper." That blank space shouldn't be there: it's treating my scanned letter paper as if it were A4 paper (which is longer vertically). You can see on the left-hand edge of the image where the border is darker than the rest of the paper. That darker portion of the border corresponds to where the paper would be if it were A4 paper.
Now, I'm never going to want to scan anything other than letter paper, so I change the paper size preference from Automatic to Letter, hoping this will fix it. But this makes the result much worse. Now there is a large inexplicable black artifact at the bottom of the scanned image:
So I have to switch back to using the Automatic preference, which seems to be stuck on A4 for some reason. :(
This happens the same regardless of whether I'm using text or image preference. Scanner is an HP Officejet 4630.