Alex

<img src="[[*imagetv]]" width="[[*imagetv:imgsize=`w`]]" height="[[*imagetv:imgsize=`h`]]" />

$img = MODX_BASE_PATH . $input;
list ($width, $height, $type, $attr) = getimagesize($img);
switch ($options) {
    case 'w' :
        return $width;
        break;
    case 'h' :
        return $height;
        break;
    default :
        return '';
        break;
}

<?php
/* @var modX $modx */
/* @var modContext $ctxs */
$ctxs_obj = $modx->getCollection('modContext', array('key:!=' => "mgr"));
$ctxs = [];
if ($ctxs_obj) {
    foreach ($ctxs_obj as $ctx) {
        $ctxs[] = $ctx->key;
    }
}

return implode(",", $ctxs);

[[!pdoSitemap?
    &tpl=`@INLINE [[+url]][[+date]]`
    &where=`{"hidemenu":0}`
    &context=`[[contextKeys]]`
]]

<?php
/* @var modX $modx */
$context_key = 'abc';
$context_resID = '317';

//Опция site_url
$site_url = $modx->getOption('site_url', array('context_key'=>$context_key));
var_dump($site_url);

//Поуличить ресурс из котекста
/* @var modResource $resource*/
$resource = $modx->getObject('modResource', array('id'=>$context_resID, 'context_key'=>$context_key));
if ($resource){
    var_dump($resource->pagetitle ." | ".$resource->id);
}

$contextKey = "yourcontext";
$ctx = $modx->getContext($contextKey);
$settings = $ctx->config;
$siteStart = $settings["site_start"];

$modx->resource->get('id')