The processTV snippet goes into your tpl chunk that contains the thumbnail source.
http://rtfm.modx.com/extras/revo/wayfinder
Template Parameters
These parameters specify the chunks that contain the templates that will drive the generation of Wayfinder's output.
With the current version of WayFinder in Revolution, you can access your own custom TVs by using a placeholder without the 'wf.' prefix, e.g. [[+my_TV]]
As of this writing, only the raw TV value will be returned: it will not be formatted. E.g. if your TV is an image, normal use of the TV inside your template would return the full image tag, but inside of a WayFinder tpl, only the path to the image will be returned.
If you want MODX 2.x to process a TV (e.g. an image TV with a base path/url as an input option (since MODX 2.1.x) or with an @inherit value) you might do that by calling a snippet within the wayfinder row template (&rowTpl). Let's say, your image TV is named icon. Normally you would use some code thing like this:
... <img src="[[+icon]]" /> ...
But it will not get you the fully processes TV. Just change your code to this:
... <img src="[[processTV? &myId=`[[+id]]` &myTV=`icon` ]]" /> ...
Within the snippet processTV you place this php-code:
<?php
$doc = $modx->getObject('modResource', $myId);
return $doc->getTVValue($myTV);
As a result the full processed image TV is returned.
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