I've got a problem after item image loading.

I got all the six different sizes of the image well sized, but the small one. Other ones have width as they should (i.e. as I setted in k2 parameters menu), but "blablabla_S.jpg" has 50px of width whatever I do.

I'm using k2 v2.5.7 and joomla 2.5.9 on Ubuntu 12.04