Sat 18-Aug-12 05:49 PM | edited Sat 18-Aug-12 05:50 PM by FrankSRGB
When you load the image, and if you have enough time to do it, try double-clicking the magnifying glass icon to punch the image up to 100% _before_ the "updating image" message goes away.
If sharpness doesn't get reduced at 100% after the updating image message goes away, you're probably seeing the result of dithering. IOW at 25% you're only seeing 1 in 4 of the available pixels. Something's gotta go and edges are not immune.