First of all we already have topic thumbnails you can enable it from the ACP.
If that isn't enough you can take a look at the code that makes it work and duplicate that.
First off, thanks for this amazing open source project!
I've set up a forum for our community and everything has gone ok so far. However, I don't want to collect email addresses because of the privacy legislation that applies in our country. Not collecting email addresses makes compliance a lot easier. Validating user email addresses for communication is not important, as password resets etc will be managed by direct communication with users outside the forum.
I noticed that it's possible to force logins with username only, but the email field is still required when signing up.
Is there an easy way to remove the email address from the signup process without breaking other parts of the forum?
There's no easy way. What privacy legislation are you referring to?