OK, I believe I found the cause to issue number two. Between lines 185 - 204 in showproduct.php:
Code:
Content visible to verified customers only.
We are using a custom usergroup to allow only certain users to upload/mod listings. We do not require administrator approval for these listings. Regular registered users aren't allowed to post listings.
The above code will not add the 'name' property to the img tag if the listing isn't flagged as approved:
Code:
Content visible to verified customers only.
Since we don't require approval for uploads, it's not adding the name, which is required for the JavaScript function update() to work.
I'm not sure if this is a bug or if we are a special case due to our chosen settings....
I'm still unable to figure out issue number one, listed in this thread's original post. Any assitance with that is appreciated.