foreach ($records as $r) {
  if (is_object($r)) $r = $r->toArray('',false,false,true);
  $r['idx'] = $i;
...

public function format($records,$innerTpl,$outerTpl=null,$firstTpl=null,$lastTpl=null,$onOne='innerTpl',$cnt=0) {
        if (empty($records)) {
            return '';
        }

        // A Chunk Name was passed
        $use_tmp_chunk = false;
        if (!$innerChunk = $this->modx->getObject('modChunk', array('name' => $innerTpl))) {
            $use_tmp_chunk = true;
        }

        $out = '';
        $i = 1;
        foreach ($records as $r) {
            if (is_object($r)) $r = $r->toArray('',false,false,true); // Handle xPDO objects
            if ($cnt == 1) {
                // Real Chunk
                if ($singleChunk = $this->modx->getObject('modChunk', array('name' => $$onOne))) {
                    $out .= $this->modx->getChunk($$onOne, $r);
                }
                // Formatting String
                else {
                    $uniqid = uniqid() . $i;
                    $singleChunk = $this->modx->newObject('modChunk', array('name' => "{tmp-inner}-{$uniqid}"));
                    $singleChunk->setCacheable(false);    
                    $out .= $singleChunk->process($r, $$onOne); // <-- gulp.
                }
                break;
            }
            // First
            if ($i == 1) {
                // Real Chunk
                if ($singleChunk = $this->modx->getObject('modChunk', array('name' => $firstTpl))) {
                    $out .= $this->modx->getChunk($firstTpl, $r);
                }
                // Formatting String
                else {
                    $uniqid = uniqid() . $i;
                    $singleChunk = $this->modx->newObject('modChunk', array('name' => "{tmp-inner}-{$uniqid}"));
                    $singleChunk->setCacheable(false);    
                    $out .= $singleChunk->process($r, $firstTpl);                    
                }          
            }
            // Last
            elseif ($i == $cnt) {
                // Real Chunk
                if ($singleChunk = $this->modx->getObject('modChunk', array('name' => $lastTpl))) {
                    $out .= $this->modx->getChunk($lastTpl, $r);
                }
                // Formatting String
                else {
                    $uniqid = uniqid() . $i;
                    $singleChunk = $this->modx->newObject('modChunk', array('name' => "{tmp-inner}-{$uniqid}"));
                    $singleChunk->setCacheable(false);    
                    $out .= $singleChunk->process($r, $lastTpl);                    
                }            
            }
            else {
                // Use a temporary Chunk when dealing with raw formatting strings
                if ($use_tmp_chunk) {
                    $uniqid = uniqid() . $i;
                    $innerChunk = $this->modx->newObject('modChunk', array('name' => "{tmp-inner}-{$uniqid}"));
                    $innerChunk->setCacheable(false);    
                    $out .= $innerChunk->process($r, $innerTpl);
                }
                // Use getChunk when a chunk name was passed
                else {
                    $out .= $this->modx->getChunk($innerTpl, $r);
                }
            }
            $i++;
        }
        
        if ($outerTpl) {
            $props = array('content'=>$out);
            // Formatting String
            if (!$outerChunk = $this->modx->getObject('modChunk', array('name' => $outerTpl))) {  
                $uniqid = uniqid();
                $outerChunk = $this->modx->newObject('modChunk', array('name' => "{tmp-outer}-{$uniqid}"));
                $outerChunk->setCacheable(false);    
                return $outerChunk->process($props, $outerTpl);        
            }
            // Chunk Name
            else {
                return $this->modx->getChunk($outerTpl, $props);
            }
        }
        return $out;
    }

<?php
/**
 * @name getPageAssets
 * @description Returns a list of images or other assets for the given page
 *
 * 
 * USAGE EXAMPLES
 *
 * You can use the resize output filter to display different sizes. 
 *
 *  [[getPageAssets? &innerTpl=`<li><img src="[[+asset_id:resize=`300x500`]]" width="300" height="500" alt="[[+Asset.alt]]" /></li>`]]
 *
 * If using the "resize" output filter, you MUST call the snippet cached! Otherwise the "resize" filter attempts to operate on the placeholder
 * before it's set!
 *
 * No results: use a MODX output filter:
 *
 *  [[getPageAssets:empty=`No images found`? ]]
 
 * Available Placeholders
 * ---------------------------------------
 * e.g. to format the original image: 
 *      <img src="[[+Asset.url]]" width="[[+Asset.width]]" height="[[+Asset.height]]" alt="[[+Asset.alt]]" />
 * or the standard Thumbnail:
 *      <img src="[[+Asset.thumbnail_url]]" width="[[+Asset.thumbnail_width]]" height="[[+Asset.thumbnail_height]]" alt="[[+Asset.alt]]" />
 *
 * If needed, include the System Settings (double ++) :
 *      [[++assman.thumbnail_width]]
 *      [[++assman.thumbnail_height]]
 * e.g. <img src="[[+Asset.thumbnail_url]]" width="[[++assman.thumbnail_width]]" height="[[++assman.thumbnail_width]]" alt="[[+Asset.alt]]"/>
 * 
 * 
 *
 *
 * Parameters
 * -----------------------------
 * @param integer $page_id of the page whose images you want. Defaults to the current page.
 * @param string $outerTpl Format the Outer Wrapper of List (Optional)
 * @param string $innerTpl Format the Inner Item of List
 * @param string $firstTpl Format the first Item of List (optional : defaults to innerTpl)
 * @param string $lastTpl Format the last Item of List (optional : defaults to innerTpl)
 * @param string $onOne which tpl to use if there is only 1 result: innerTpl, firstTpl, or lastTpl. Default: innerTpl
 * @param string $group optional: limit the results to the specified group
 * @param boolean $is_active Get all active records only
 * @param boolean $is_image if true, return only images, if false, only other assets. If not set, we get everything.
 * @param int $limit Limit the records to be shown (if set to 0, all records will be pulled)
 * @param string $sort which column should we sort by?  Default: Product.seq
 * @param string $dir which direction should results be returned?  ASC or DESC (optional)

 *
 * Variables
 * ---------
 * @var $modx modX
 * @var $scriptProperties array
 *
 * Usage
 * ------------------------------------------------------------
 * To get all Images on certain page
 * [[!getPageAssets? &page_id=`[[*id]]` &outerTpl=`sometpl` &innerTpl=`othertpl` &firstCLass=`first` &is_active=`1` &limit=`0`]]
 * [[!getPageAssets? &page_id=`[[*id]]` &outerTpl=`sometpl` &innerTpl=`othertpl` &is_active=`1` &limit=`1`]]
 *
 * @package assman
 */

$core_path = $modx->getOption('assman.core_path', null, MODX_CORE_PATH.'components/assman/');
require_once $core_path .'vendor/autoload.php';
$Snippet = new \Assman\Snippet($modx);
$Snippet->log('getProductImages',$scriptProperties);


// Formatting Arguments:
$innerTpl = $modx->getOption('innerTpl', $scriptProperties, '<li><img src="[[+Asset.url]]" width="[[+Asset.width]]" height="[[+Asset.height]]" alt="[[+Asset.alt]]" /></li>', true);
$outerTpl = $modx->getOption('outerTpl', $scriptProperties, '<ul>[[+content]]</ul>', true);
$firstTpl = $modx->getOption('firstTpl', $scriptProperties, $innerTpl, true);
$lastTpl = $modx->getOption('lastTpl', $scriptProperties, $innerTpl, true);
$onOne = $modx->getOption('onOne', $scriptProperties, 'innerTpl', true);
$sort = $modx->getOption('sort', $scriptProperties, '`PageAsset`.`seq`', true);
$dir = $modx->getOption('dir', $scriptProperties);

// Default Arguments:
$scriptProperties['is_active'] = (bool) $modx->getOption('is_active',$scriptProperties, 1);
$scriptProperties['limit'] = (int) $modx->getOption('limit',$scriptProperties, null);
$page_id = (int) $modx->getOption('page_id',$scriptProperties);

// Just being safe in case this is run without a resource in context
if (!$page_id) {
    if (isset($modx->resource) && is_object($modx->resource)) {
        $page_id = $modx->resource->get('id');
    }
}

if (!$page_id) {
    return 'Page ID is required.';
}

$criteria = array();
$criteria['page_id'] = $page_id;
$criteria['PageAsset.is_active'] = true;
if (isset($scriptProperties['is_image']) && $scriptProperties['is_image'] !== '') {
    $criteria['Asset.is_image'] = (bool) $scriptProperties['is_image'];
}
if (isset($scriptProperties['group']) && $scriptProperties['group'] !== '') {
    $criteria['PageAsset.group'] = $scriptProperties['group'];
}

$c = $modx->newQuery('PageAsset');
$c->where($criteria);
if ($sort && $dir) {
    $c->sortby($sort,$dir);
}
elseif($sort) {
    $c->sortby($sort);
}
if ($scriptProperties['limit']) {
    $c->limit($scriptProperties['limit']);
}

$PageAsset = $modx->getCollectionGraph('PageAsset','{"Asset":{}}', $c);
$cnt = count($PageAsset);

if ($PageAsset) {
    return $Snippet->format($PageAsset,$innerTpl,$outerTpl,$firstTpl,$lastTpl,$onOne,$cnt);
}

$modx->log(\modX::LOG_LEVEL_DEBUG, "No results found",'','getPageAssets',__LINE__);

return;