BuddyPress.org

Hi I am building a site with BuddyPress for a community ( about 2000 users ) this site is designed to be a dating /social network site.
(no forums no blogs no chat)
Just the options to send private messages
open groups and comment,
adding friends ,
creating personal profile.
Because I have never built a large scale website and I do it voluntarily and also storing it on my personal site server, I have a few issues I am asking for your advice:
From your own experience or links to good articles and references.
Should I allow the members to upload many images? My concerns are: viruses ,taking up data space , and copyright issues.
How do you deal with cyber bullying users who are harassing other users trolls writing nasty comments(I really want this community website to be a safe place:)
Your experience with the security issues (Trojan virus etc)
Any Other important issues I should know?
Any help will be very very appreciated.