OT: scaling images

[Enrique Arredondo]

Hi,

I need to rescale lots of images keeping the same ratio, the output has to 
be 1500x1500 and the problem I'm having is that if the image is 1500x634 , 
I don't know how to make that 1500-634 pixel difference white. Any Ideas ?

Thanks

This is what I do to get to the 1500:

/usr/bin/djpeg atk2a03-2.jpg | pamscale -xyfit 1500 1500 | /usr/bin/cjpeg 
> newatk2a03-2.jpg