Answered Output filter

can't see anything, why this shouldn't work, then.

How do you call the snippet?
Did you try to place the placholders directly after the snippet-call?

are you trying to get the images from the iterated resources?
Then you will need to pass the resource-id to your snippet and get the TV of that resource.

$values = explode(',',$modx->resource->getTVValue('IMAGE'));
$first = $values[0];
$second = $values[1];
$third = $values[2];
$modx->setPlaceholder('path1',$first);
$modx->setPlaceholder('path2',$second);
$modx->setPlaceholder('path3',$third);
return '';

$values = explode(',',$modx->resource->getTVValue('IMAGE'));
$i = 1;
foreach ($values as $value){
    $modx->setPlaceholder('path'.$i,$value);
    $i++;
}
 
return '';

<!--?php

$docid = $modx--->getOption('docid',$scriptProperties,$modx->resource->get('id'));
if ($resource = $modx->getObject('modResource',$docid)){
    $values = explode(',',$resource->getTVValue('IMAGE'));
    $i = 1;
    foreach ($values as $value){
        $modx->setPlaceholder('path'.$i,$value);
        $i++;
    }    
}
  
return '';

and call it with

&docid=`[[+id]]`

<!--?php

$docid = $modx--->getOption('docid',$scriptProperties,$modx->resource->get('id'));
if ($resource = $modx->getObject('modResource',$docid)){
    $values = explode(',',$resource->getTVValue('IMAGE'));
    $i = 1;
    foreach ($values as $value){
        $modx->setPlaceholder('path'.$i,$value);
        $i++;
    }    
}
  
return '';

and call it with

&docid=`[[+id]]`