Dynamic templates use PHP and are not able to access the perl-script you've created. You will see something like the following error message when loading your site: "Smarty error: syntax error: unrecognized tag ...". So you're googling and find a lot of people with the same problem. But no one seems to has a solution. So keep on reading. Here it comes.
You might have read the instructions about creating the php folder in your plugin directory. But what to put in there. Because it uses smarty tags, you must create a php function smarty can use. So there are special naming requirements for the php file and the function name.
The file must be called function.mtmyimageurl.php (if you follow the documentation on movabletype.org). Inside create a function
function smarty_function_mtmyimageurl($args, &$ctx) {
$movableType = $ctx->mt;
return $movableType->config('myimageurl');
}
Please keep to lowercase filenames and function names. Or it just might not work.
