welche version von GD ist installiert? bei den neueren kannst du, afair keine gif-dateien mehr manipulieren, da das lizenzrecht da schwierigkeiten macht.
die methode $image->copyResized könnte für dich, wenn ich das richtig verstanden habe, von interesse sein:
http://search.cpan.org/~lds/GD-2.11/GD.pm
Quote$image->copyResized($sourceImage,$dstX,$dstY,
$srcX,$srcY,$destW,$destH,$srcW,$srcH)
This method is similar to copy() but allows you to choose different sizes for the source and destination rectangles. The source and destination rectangle's are specified independently by (srcW,srcH) and (destW,destH) respectively. copyResized() will stretch or shrink the image to accomodate the size requirements.
Example:
$myImage = new GD::Image(100,100);
... various drawing stuff ...
$srcImage = new GD::Image(50,50);
... more drawing stuff ...
# copy a 25x25 pixel region from $srcImage to
# a larger rectangle starting at (10,10) in $myImage
$myImage->copyResized($srcImage,10,10,0,0,50,50,25,25);