Graphichs dialog:The "maintain aspect ratio" checkbox has the tooltip text "Scale image to maximum size not exceeding width and height"
This looks like misinformation to me. I never had the impression that this checkbox maximized the size in any way. It maintains correct aspect ratio, for example when I specify an exact width and no height. The image may very well be small - i.e. not maximized in any way.
Helge Hafting