well, the original images are really various sizes, i always resize them before uploading, and some of them are already cropped, so they are not all standard resolution, but for all of the thumbs was expecting that a crop will crop fixed size 140x120 no matter what the original resolution is. Anyway, its not a big tragedy, i "solved" it with giving the containing div for every thumbnail a fixed width of 140 pixels, so its not very obvious that some of the thumbs are 1 pixel smaller than others :) otherwise with dynamic div width it ended up having rows of thumbs definitely shorter than others, which was ugly :))