think about using (client-side, html-embedded) javascript:
<form name="my_form" method="post" ...>
<input type="hidden" name="info" ...>
->
document.my_form.submit();
this submits the form without the need for a submit button.
you can hook this command to various actions, e.g.:
<body onLoad="document.my_form.submit();">
or:
<img onClick="document.my_form.submit();">
etc.