title: What to include in email headers, using php mail()?
body: <p>When I want to send email, my codes look like these:</p>
  
  <pre><code>$headers =  'MIME-Version: 1.0' . "\r\n";
  $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
  $headers .= 'From: me@localhost' . "\r\n";
  
  // Email Variables
  $toUser  = 'you@something';
  $subject = "Testing";
  $body    = '&lt;html&gt;&lt;head&gt;&lt;title&gt;&lt;/title&gt;&lt;/head&gt;&lt;body&gt;
              This is my picture &lt;img src="http://domain.com/me.jpg"&gt;';
  
  if(mail($toUser,$subject,$body,$headers)){
    echo "Email sent!!";
  }
  </code></pre>
  
  <p>Here are my questions:</p>
  
  <ol>
  <li>Must I include the <code>&lt;html&gt;, &lt;head&gt;, &lt;title&gt;...</code> tags?</li>
  <li>Can I use stylesheet? For example, <code>&lt;div style="..."&gt;</code> ?</li>
  <li>I tested send the email to several accounts, if I include the <code>&lt;img&gt;</code> tag (for include image), it goes to junk mails, but if just plain text it goes to inbox. Anyone has any idea why it is? And how to solve it?</li>
  </ol>