Created attachment 14390
Examples of truncated logos fr.wikiversity and Wikimedia UK (Konqueror 4.85/Linux/Vector/1024x768)

Attached:

Could reproduce for en.wikivoyage.org on 1440x900px in Konqueror 4.11.5 in Fedora 20.

The affected wikis have logos that are no wider than any of the others (135px).

If anything, they're actually narrower (fr.wikiversity.org has an odd 134px logo).

However most logos (those made by the design team or those customised in a way that is in line with the original versions) have a fair amount of breathing room included in the image.

Konqueror has a consistent rendering of 120px where the 135px image is located. So it's always being cropped, on all wikis.

But those wikis with customised logos without the breathing room are more visibly cut off (cutting into visible pixels instead of transparent margin).

The width is specified as "10em" in Vector based on font-size "html { font-size: 100%; }". This is not a very reliable way to render a fixed-width image indeed. Presumably the default font size in Konqueror is just tad smaller than most browsers.

Perhaps we should add a min-width: to the Vector sidebar?

PS: Monobook is subject to the same bug, though it specifies a width of 12.2em, so the font-size would have to be a lot smaller for that to resolve to 120px.