So I'm getting this error in one of my galleries..

Zenphoto Error
MySQL Query ( INSERT INTO zp_obj_to_tag(objectid, tagid, type) VALUES (300,,'images') ) failed. Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''images')' at line 1

Any idea?

Check your database. The tags table should have a field named id which is set to autoincrement. I'm guessing it is not set to autoincrement.

Thanks for the quick response. I did check the mysql table and it id field is set properly to autoincrement. Could the issue be caused by a bad image file or non supported version of a jpeg or png?

I doubt it. The ID field from a query came back empty. That cannot happen with autoincrement. Maybe there is a record with an empty ID?