Default avatar collection is not losslessly compressed

When you edit your profile, you get to pick an icon representing you and are offered a set of predefined images. Looks like Trimage can shave bits off these.

While losing 2 kB or so per image might not seem like a big deal, it does cumulate. Also, it makes the forum unnecessarily slower.

I guess this epiphany should also be communicated upstream so that every Drupal install would get fit.