I have a similar problem to user Niecher. http://forum.coppermine-gallery.net/index.php/topic,76024.0.html (http://forum.coppermine-gallery.net/index.php/topic,76024.0.html)
My host only allows a certain amount of server memory to PHP for computing. This greatly limits the image size.
I will get an out of memory error on pictures larger than 3000x3000. Therefore, I resize all images above 3000x3000
to 3000x3000 before uploading. This way I get no memory errors when batch uploading.
Once the album is generated and info is in the database, I upload the fullsize images over the reduced size images.
When a visitor clicks for a fullsize image they get the true fullsize image. This has been working for almost four years.
Is there a way to correct the filesize data and dimensions data without coppermine trying to create new thumbnails and intermediate images?
Gallery Configuration - Coppermine Photo Gallery 1.5.22 (stable)
http://documentation.coppermine-gallery.net/en/admin-tools.htm#admin_tools_options_reload_dimensions