Okay.
1. Install phpMyAdmin, get it from
http://phpmyadmin.net2. Using phpMyAdmin, export the 4images categories table
3. Open the exported text file in an editor.
4. Do a search and replace on the values you want changed.
5. Using phpMyAdmin, import the edited file back into the database.
*** KEEP A CLEAN BACKUP OF YOUR TABLE IN CASE OF A MISTAKE! ***[/list:u]
That's what I would do.
P.S.: You could also use the admin control panel>"Backup Database" to download the table, make the edit, upload by FTP to 4images/data/database, and then restore the table.