Well, here's my 2 bits. I have no Idea how to do this, but you'd probably want to SQL - query the photopost DB row for User, and have an if statement, saying, if their name shows up:
PHP Code:
eval( '$ppbutton = "' . gettemplate( 'showthread_ppbutt' ) . '";' );
and if not, then set it to nothing.... *wishes someone would explain vbulletin mySQL queriying syntax to him*
That'd be on the showthread page, and you'd put $ppbutton in the postbit template...