Other in KDE Base
KIconLoader now returns more quality icons if the requested size is not a standard one. This means that if the size requested is not standard it will try to load the icon from the SVG format before than trying to load the PNG image and then resizing it (what leads to a worse image quality).
In the case that not SVG was found and PNG was, the change on KIconTheme assures that it will stop on the closest size bigger than the selected (for example, it will stop on 22x22 if you requested a 19x19 pixels icon size) and then resize it.
This will only happen if the SVG wasn't found. If the size is a standard one, go on with the normal procedure: load the PNG that is faster than drawing a SVG and since no resizes are needed no quality is lost.