Not understanding this code

[SilverDragonTears]

If anyone can help I'm trying to insert yes or no allow alternateimages and i'm testing it out on the ones that have alt images but keep getting no. So I want to know if this code even works that I put together and what is the odds of getting an alt image?

$rarealts = $adopt->getRareAltStatus();{
        if($this->rarealts == "enabled" and $this->currentlevel == $this->altoutlevel){
            $rand = mt_rand(1, $this->altchance);
            if($rand == 1) $userarealternates = "yes";            
        }
        else $userarealternates = "no";
    }