I see examples like below, but have no idea where I would put them on image.php of the homepage.:
Format: $('selector').colorbox({key:value, key:value, key:value}, callback);
Example: $('a#login').colorbox({transition:'fade', speed:500});
Example: $('a.gallery').colorbox();
Example: $('button').colorbox({href:"thankyou.html"});
And it can be called directly, without assignment to an element
Example: $.colorbox({href:"thankyou.html"});
ColorBox can accept a function in place of a static value:
$("a[rel='example']").colorbox({title: function(){
var url = $(this).attr('href');
return 'Open In New Window';
}});