I need to tidy up the database

[NatalieFord]

...because it seems to contain links to files that no longer exist (e.g. http://natalieford.com/photos/thumbnails.php?album=2&page=3). How should I remove these links from the database?

[Casper]

This happens when you remove things by ftp, or you used a database dump when you moved from another server, but did not bring all the pics with you.

If you still have those pics, ftp them into the folder they used to be in.  Then use coppermine to delete them.  otherwise, you will have to edit the database pictures table, and manually remove the entries for these pics.

[NatalieFord]

This happens when you remove things by ftp

Yep. I learnt the hard way.

If you still have those pics, ftp them into the folder they used to be in.

They no longer exist.

Otherwise, you will have to edit the database pictures table, and manually remove the entries for these pics.

That is what I thought. How do I do that? What access do I need? What tools?

[Casper]

Whatever tool your host provides for your use, something like phpMyAdmin.

With that you can do anything you want to the database.  Be aware, it is very easy to cock it all up when you don't know what you're doing.

Before you do anything else, you should make a backup(dump) of the database, so you can restore everything if it goes wrong.

You should regularly make a back-up anyway.