OK so find one character that has the right size port save that sprite and then you will have to take the one that's smaller open both in gimp take the big one and click image mode rgb on the bigger one put the smaller one on top of the bigger one resize the small one to fit over the big one go to image mode index it to 255 now go to color image map and make sure the background color is placed at zero save changes then save as png put it back in to fighter factory and now you have a bigger port let me know if this helped or if you have any problems