Custom shortcode to display the user's Gravatar on the View based on an email field.

gvgravatar.php

<?php // remove this whole line when copying this code to your theme's function.php file
add_shortcode( 'gvgravatar', 'gv_gravatar_shortcode' );
function gv_gravatar_shortcode( $atts ) {
	extract( shortcode_atts(
		array(
			'email' => '',
		), $atts )
	);
	$md5 = md5($email);
	$image = '<img src="https://secure.gravatar.com/avatar/'.$md5.'?s=55">';
	return $image;
}

// usage: inside a custom content field, add the shortcode [gvgravatar email="{Merge Tag of the form field containing the email}"]