That not strecthing.. thats shrinking
Ok .. I'm going by my memory here .. no PS or IR right now ...
The tool that u need first is not image ->resize, but image->crop .. You need to select with marquee tool first so you get a perfect square .. Press shift
while selecting the area you want ... you should get a 75 x 75 square .. now make sure that the part you want (you can move the area selection around), go to image -> crop
.. You get a nice square of 75 x 75 gif ... Then go to image -> image size
, ensure that constrain proportion
checkbox is checked (most importantly) .. then put in a 100 in either the width
.. it shouldnt matter since when u put a value, the other while resize to correct proportion size.. in our square gif, it should be a 100 as well ..
Sorry i couldnt make a screenshot explaining these step .. but try and see if you can follow it ^^