Let's say I have the following URL: pic.php?t=1&p=23
When I try phpThumb.php?src=/pic.php?t=1&p=23, I get Forbidden parameter: p.
Anyone knows if there's a way around it?
You need to URLEncode that ampersand if you are trying to pass p=23 to pic.php. Try replacing the & with %26.
What you are effectively doing there is passing p=23 as a parameter to phpThumb.php, which obviously it doesn't like...
What you probably want to do is 'phpThumb.php?src='.urlencode('/pic.php?t=1&p=23');