dev and production sites

hi,i have two versions of the same site (one is dev,and the other is production ) i first add the content in the dev then using back up and migrate module then i restore to the production one.and i have users accounts only in the production one so the table users is different int the 2 sites,so when i back up from the dev i exclude the users table and when i open the production site i found the users profiles pictures not correct or not exist, i knew that cause the new contents pictures take the same id in the file_mange table as the user picture on the other site so it take another path ,i tried to exclude the file_manage table also but this become worse .any ideas?