Incorrect custom image sizes in Media Manager

Hey!

I use custom image sizes on a site which up to this point has had no problem displaying them.

Once i updated to 3.5, i noticed that my custom size isnt correct in the dropdown field listing all possible sizes. The size should be 650 x 272, but i see 640 x 267 ( reduced by 2% in both cases ).

My theme is a simple child theme based on twenty ten. I do not do any sort of image processing anywhere else. I also can’t find any CSS that could create this condition.

Any ideas where i should look?

Thanks!