What's the difference between GD1 and GD2?

[Joachim Müller]

GD2 will create pictures with better quality (intermediate and thumbnails). Here's an example taken from w-nailer: about resizing
(Original pic size: 1024 x 768 pixels):

(https://coppermine-gallery.com/forum/proxy.php?request=http%3A%2F%2Fcoppermine.sourceforge.net%2Fimages%2F128x96gd1.jpg&hash=70435d518511ed9773162697ad949e1b8fd68544) GD 1.8.4: ImageCreate ImageCopyResized 128 x 96 pixels

(https://coppermine-gallery.com/forum/proxy.php?request=http%3A%2F%2Fcoppermine.sourceforge.net%2Fimages%2F128x96gd2.jpg&hash=f361ed33599a53e729a4d67f8e6a8632db538d53) GD 2.0.1: ImageCreateTrueColor ImageCopyResampled 128 x 96 pixels

Upgrading GD lib when coppermine is already installed will therefor not affect the pictures which are already created, but only new ones. You can not upgrade nor install GD lib unless you're running your own webserver - only your webhost can!