Can an inserted image be linked back to its node?

Thanks for the replies.

Just to clarify, I'll only need to know about files added to fields, not files embedded via wysiwyg.

After migrating D6 + Image module to D7 + image entity, I now have several thousand image nodes, each with one image field. So any image entity has an image node that owns / contains it.

Now I'd like that when I insert an image into a wysiwyg text area, the image is inserted, but with anchor tags linking it back to its node. Views already knows how to do that - I can make a view that shows a grid of thumbnails, choose the Views option to "Link image to: content", then if I click the thumbnail I go to the node that contains that image.

I've read that the media browser uses views to generate the grid of images we choose from.

But I'm not sure how / if there's a way to pass those anchor tags back from the view to the code that is generating the [[ ]] tags that are inserted into the wysiwyg text.

Taking a step back, does the [[ ]] markup support links?

I've dug around a bit more, and I can't find any examples of the [[ ]] markup supporting links.

How I'd like it to work is that on the second screen of the Media Browser (where the user chooses the format), there would also be an option to choose the destination link, similar to the options in Image Assist:

Link:
- Not a link : the current behaviour.
- Link to media: eg for a local PDF, links to the file on the local server. eg for a Flickr photo, links to the page on Flickr for that photo.
- Link to referencing entity: This is my use-case - links to the Node that contains the Media entity. For an image, that could be a page with additional information and comments about the photo, and a high-resolution copy of the embedded image.
- Link to URL: User can specify the link.

But a simpler start could be to allow a file type display to pass a url to the code that's building the [[]] markup, and then alter the code that processes the markup to wrap the anchor tags for that url around the media.

There are several issues about inserting links to PDF files, eg http://drupal.org/node/1568474. A reply there points to related issues:
http://drupal.org/node/1451316
http://drupal.org/node/1283844
http://drupal.org/node/1016376

I'll try and understand those better.

Initial requirement is to replicate current D6 Image Assist behaviour. So every image embedded into a WYSIWYG text area using the D7 Media Browser should be linked back to the node it belongs to. For the way our site is configured we can assume that there is a one-to-one mapping between an image entity and a node.

To identify the image entity's node, a couple of ideas:

• Modify the Media Browser to send additional information about the selected image (ie the nid of its node, which Views knows about), and include the nid as an extra parameter in the '[[]]' macro.
• Or just store the fid in the macro, and work back from the fid at runtime to work out which node contains this entity

Once we know the node, at some point during generating the html we need to add the anchor tags around the image)to give a link back to the node. How do we insert the change into the Drupal flow of building a page?

• 'File Entity Link' implements a 'hook_theme, so that's one option
• There look to be other hooks available too.
• Not sure which is best way yet

How is this packaged up and presented to the administrator?

• create a new formatter? Could be a quick way to get it working. Eg I currently need to use the 'Image' display. Could I create a new display (I think 'display' and 'formatter' have the same meaning here?) called 'Image linked to node'. It would call the existing 'Image' display to generate the current html, then wrap the extra anchor tags around it.
• Another way is to provide an option independent of the choice of formatter. This is how the 'File Entity Link' appears, displaying a "Link file to referencing entity" checkbox. That could work too.

Here's what I ended up doing, in case anyone else has a similar requirement. Looking back it does what Damien suggested in #1 - thanks for the tips.

It's my first code for media (and first for D7), so if you can see any better ways to do this, please let me know.

Regards, David

/**
* Implements hook_media_token_to_markup_alter. It wraps the <a> tag around 
* the image, to link it to the node.
*
* This is called near the end of media_token_to_markup(). 
* media_token_to_markup() takes the media token (ie the "[[]]" string 
* that represents an embedded media file) and passes the information
* to the correct file displays (aka formatters) so they can build a 
* render array. This function is called just before the render array 
* is rendered into HTML.
*
* On our site, all media entities (ie photos) are stored as part of a 
* node (the result of upgrading D6 Image module's nodes). Whenever a photo is 
* inserted into text via Media Browser, we want that photo linked back to
* its node, so a reader can click the photo and visit the node to learn 
* more about the photo.
*
* @param $element
*   Contains the render array, which we modify.
*
* @param $tag_info
* @param $settings
*   not used.
*   
*/
function YOURMODULENAME_media_token_to_markup_alter( &$element, $tag_info, $settings) {
	// The token-to-markup happens in two cases:
	//  1. When the WYSIWYG editor displays the text for editing
	//  2. When the saved text is displayed. 
	// Only add the link in case #2.
	if ($file->override['wysiwyg']) {
		return;
	} ;

  // Find which node is using this file. (There should always be one and 
  // only one node / file combination on our site.)
  $file = $element['#file'] ;
  $usage = file_usage_list( $file ) ;
	foreach ($usage as $module => $entity_types) {
    foreach ($entity_types as $entity_type => $entities) {
			foreach ($entities as $entity_id => $count) {
				if (($entity_type == 'node') && (!isset($nid))) {
					$nid = $entity_id ;
				}
			}
		}
  }
  if (!isset($nid)) {
		return;
	} ;

	// It would be better if the render array for a media object
	// had a '#path' field to specify a target url, the same way that
	// core image fields do (see http://data.agaric.com/wrapping-link-around-renderable-array-images-drupal-7)
	// But I don't think '#path' is supported, at least I couldn't make 
	// it work. The following way probably isn't the best, but seems to 
	// work ok.
	// We push the original render array down a level, and add the 
	// <a> tags like this:
	$new_element = array(
		'#prefix' => '<a href="/node/' . $nid. '">',
		'#suffix' => '</a>',
		'media' => $element,
	)	;
	$element = $new_element ;		
}