Index: media.php
===================================================================
--- media.php	(revision 21186)
+++ media.php	(working copy)
@@ -778,12 +778,30 @@
 	elseif ( $url_type == 'post' )
 		$url = $link;
 
-	return "
-	<input type='text' class='text urlfield' name='attachments[$post->ID][url]' value='" . esc_attr($url) . "' /><br />
-	<button type='button' class='button urlnone' data-link-url=''>" . __('None') . "</button>
-	<button type='button' class='button urlfile' data-link-url='" . esc_attr($file) . "'>" . __('File URL') . "</button>
-	<button type='button' class='button urlpost' data-link-url='" . esc_attr($link) . "'>" . __('Attachment Post URL') . "</button>
-";
+	if ( substr($post->post_mime_type, 0, 5) == 'image' ) {
+		$large_image_array = wp_get_attachment_image_src( $post->ID, 'large' );
+		$large_image = $large_image_array[0];
+		$url = $large_image;
+		$enabled = ( $file != $large_image ); // Disable the large image button if it is the same as the full size image
+	}
+	
+	$image_link_input_fields_html = "
+		<input type='text' class='text urlfield' name='attachments[$post->ID][url]' value='" . esc_attr( $url ) . "' /><br />
+		<button type='button' class='button urlnone' data-link-url=''>" . __( 'None' ) . "</button>
+	";
+	if ( ! empty( $large_image ) )
+		$image_link_input_fields_html .= "
+		<button type='button' class='button urlfile' data-link-url='" . esc_attr( $large_image ) . "'" . disabled( $enabled, false, false ) . ">" . __( 'Large Image' ) . "</button>
+		<button type='button' class='button urlfile' data-link-url='" . esc_attr( $file ) . "'>" . __( 'Full Size Image' ) . "</button>
+	"; else
+		$image_link_input_fields_html .= "
+		<button type='button' class='button urlfile' data-link-url='" . esc_attr( $file ) . "'>" . __( 'File URL' ) . "</button>
+	";
+	$image_link_input_fields_html .= "
+		<button type='button' class='button urlpost' data-link-url='" . esc_attr( $link ) . "'>" . __( 'Attachment Post URL' ) . "</button>
+	";
+	
+	return $image_link_input_fields_html;
 }
 
 function wp_caption_input_textarea($edit_post) {