Comment 41 for bug 891586

The driver bug I'm referring to is:

2CV67 Epson Perfection V200 scanimage
    --resolution 300|2400|4800dpi [300]
        Sets the resolution of the scanned image.
    --x-resolution 75|300|600|1200|2400|4800dpi [300]
        Sets the horizontal resolution of the scanned image.
    --y-resolution 100|200|300|400|600|800|1200|1800|2400|3600|4800|6600|9600dpi [300]
        Sets the vertical resolution of the scanned image.

I'd expect --resolution to be able to take 300|600|1200|2400|4800 if it is a shortcut for setting the x and y resolution independently.

So the logic simple scan should take is:
1. Use --resolution if it exists and has a value we require
2. Use --x-resolution, --y-resolution if they exist and contain the values we require
3. Do the closest match using 1 or 2
4. Do not set resolution