making thumbs

I have thumbs that are 150 x 150 and I need to make 180 x 135 out of it. I was wondering if there is a way to (first make it 180 x 180) set Rectangular Marquee Tool to 180 x 135 and just put it on the picture and copy that exact size and paste it to a new file.

Thanks.

>>> I already found it by myself...

To do the job quicker just use the crop tool and set it for the size you want in pixels but fist duplicate your image folder.