Wrong number of pics per page

Yesideez

I've got 27 pictures contained in an album and 15 pics per page set yet I'm getting 18.

I've searched just in case others have had the same issue and the results I found I tried and nothing has worked.

I changed this:
[code]while (next_image(false, $firstPageImages)):[/code]
to this:
[code]while (next_image()):[/code]

and no change. I also saw the mention of changing line 4 to this:
[code]$firstPageImages=0;[/code]

Only problem is, line 4 is actually "</head>" so I've no idea where this is supposed to go!