I have +600 members in my gallery and I want the intergrate the gallery with smf forum without losing any of the members in the gallery.
Will I lose anything if I do it normally?
Or do I add every member 1by1?
You need to convert the users to SMF users. There is no tool available to do this afaik.
See Documentation > Integrating the script with your bulletin board > Coppermine users, groups and pics uploaded by users are lost when integrating (http://coppermine-gallery.net/demo/cpg14x/docs/index.htm#integrating_users_start):
QuoteWarning: If you already have users and custom groups in your coppermine database when you enable bbs integration, be aware that they will be lost. If your coppermine users have already created private albums and uploaded pics to them, they will be lost as well!