Here is the form 

<form method=get 
      name=form1 
      action="http://address
 .
 .
 .
  
 
          <input type="image" 
               alt=" Go " 
               src="http://address/image.gif" 
               border=0> 
          <a href="http://address"> 
          <img src="http://whatever/f-clear0.gif" border=0 
       alt="Clear"></a> 
        
</form> 

Here is the code:

use WWW::Mechanize;

my $agent = WWW::Mechanize->new();
$agent->get('http://address');
$agent->form(1);
$agent->field(qw(request test));
#tried this but it didn't work
#$agent->find_image(alt => " Go ");
#$agent->click();
$agent->submit("Go");

print $agent->{content};