This doesn't happen every time, just from time to time but it's very annoying.
When uploading images via batchadd it sometimes takes a while longer for the server to run through the process and this seems to cause the gallery to duplicate one or two images, and upload two for the price of one. It doesn't rename the file when uploaded so it's obvious it's the same image file on the server, only the gallery is displaying it twice in the album - not the server.
Example:
http://dana.thedudes.nu/gallery/displayimage.php?album=565&pos=11
http://dana.thedudes.nu/gallery/displayimage.php?album=565&pos=12
Same image twice. I've tried to delete one but of course the other one gets deleted then too since it's the same basic file on the server.
What can I do to stop this and remove the doppelgangers?
Read the sticky thread? Performed the steps as described there? Please do so before posting.
http://forum.coppermine-gallery.net/index.php/topic,24088.0.html (http://forum.coppermine-gallery.net/index.php/topic,24088.0.html)
Update first. You're using cpg1.4.10, while the most recent stable release currently is cpg1.4.19.
If your problems persist, do exactly as suggested in the docs, section "asking for support on upload issues"