In order to circumvent the PHP memory problem I followed the documentation http://coppermine-gallery.net/demo/cpg14x/docs/index.htm#upload_error_messages (http://coppermine-gallery.net/demo/cpg14x/docs/index.htm#upload_error_messages):
However, following "Alternative 3" when I click through to the full-size images they are still displayed in a window that was the size of the smaller images that were originally loaded. Having overwritten the images with larger-dimensioned files how can I get Coppermine to display full size images with the NEW full dimensions?
Use the admin tools!