I would like to get more information about this improvement. As I checked, phpunsharpmask.php has the same parameteres as before for sharpening:
function UnsharpMask($img, $amount = 120, $radius = 0.4, $threshold = 1)
In my opinion after installing 4.5.2 I do not see any changes in good. Photos still have sharp ugly edges. I already provided you a good way for DPI and changing parameters, but QT engineers don't like ideas from outside ...
PHP Code:
[*] 24 Jul 2012, random - Improvement (0124413): Sharpening parameters adjusted to improve quality of auto-generated thumbnail images.