We have made a few changes on the server that should eliminate the dreaded "Security Token Missing" error when uploading large photos. If you still encounter a problem, please post your issue to this thread on the forums:
The only problem I can foresee is with uploading multiple large images. If you still encounter this problem it is likely going to be because you are uploading multiple large images. I can further tweak the server to accommodate the large uploads. Just let me know the total filesize (in MB) for your upload so I have an idea of how much higher I need to go to eliminate the problem altogether.