Comment 45 for bug 605567

This is almost certainly due to the huge sprite sheet that Launchpad uses. As #32 mentioned, the 64x22031 sprite sheet
https://bugs.launchpad.net/+icing/rev14914/icon-sprites
is to blame; disabling it using an ad blocker or equivalent fixes performance.

The new Dropbox design also triggers this bug, with the offender being this sprite sheet (64x30030):
https://www2.dropbox.com/static/1331165834/images/sprites/sprites.png

As more and more web applications switch to sprite sheets to reduce page loading latency, this is going to spring up more and more.