Doubt on avatars helps me!

Hello friends first would like to congratulate you for the forum because it is excellent, I like the Web Wiz a lot... good I would like to know if it is possible to alter a small detail in the Web Wiz for personal use... what alteration would be that? well I repaired that when I change the changes for a certain size in the case 160x160, and I use a smaller change than that type 64x64 the forum increases the change for 160 and it doesn't show the original size... I would like to know if it is possible to leave the picture with the right size without to increase and to lose quality as the forum does automatically....  my doubt is the following... is it possible I to put in the configurations of the forum in the options of changes in 160x160 and me to use a smaller change than the one of the forum in the case 100x100 and not to increase the picture automatically how the forum Web Wiz does???? please if somebody knows how I do to show the picture of the change with the original size without increasing thank at once... I am with that doubt because I am testing the forum in my Pc and I am having that small problem and I would like to know how to leave the picture in the original size not enlarging the picture... at once I thank even more.