Please always add the name of a 3rd party tool so its author maybe able to help.
In this case printTags() is a standard function that simply prints all tags assigned. If you want only 8 you have to create your own output for that use getTags():
http://www.zenphoto.org/documentation/functions/_template-functions.php.html#functiongetTags
General rule: Most all template functions have a print and get variant. And if not there is always the object model to do most anything directly.
There is no discontinuity between being a photographer and programming in PHP I am both. Unfortunately, if you want to customize things then acquiring some knowledge is essential.
In your case above, you need to understand that the "get" versions of functions never produce output, just return something that you then have to act on. The "print" versions are the ones that put something on the page.
So getTags returned you a list of tags. If you want them shown you have to format them for your page.