Now I find a solution wich works for me. Its a little bit custom. I defined some custom image sizes in my child theme.
This is the modyfied code in uris-layout.php
foreach($RPGP_AllPhotosDetails as $RPGP_SinglePhotoDetails) {
$Title = $RPGP_SinglePhotoDetails['rpgp_image_label'];
$Desc = $RPGP_SinglePhotoDetails['rpgp_image_desc'];
$Url = $RPGP_SinglePhotoDetails['rpgp_image_url'];
// Get the Original ID of images
$imageID = attachment_url_to_postid( $Url );
$UrlData = get_intermediate_image_sizes();
// Default Image
$DataImages_data_src = wp_get_attachment_image_src( $imageID, $UrlData[7]);
// Small Image
$DataImages_data_small = wp_get_attachment_image_src( $imageID, $UrlData[11]);
// Medium Image
$DataImages_data_medium = wp_get_attachment_image_src( $imageID, $UrlData[12]);
// Large Image
$DataImages_data_large = wp_get_attachment_image_src( $imageID, $UrlData[2]);
// Retina Image
$DataImages_data_retina = wp_get_attachment_image_src( $imageID, $UrlData[13]);
$i++;
?>
<div class="sp-slide">
<img class="sp-image" alt="<?php echo $Title; ?>" src=""
data-src="<?php echo $DataImages_data_src[0]; ?>"
data-small="<?php echo $DataImages_data_small[0]; ?>"
data-medium="<?php echo $DataImages_data_medium[0]; ?>"
data-large="<?php echo $DataImages_data_large[0]; ?>"
data-retina="<?php echo $DataImages_data_retina[0]; ?>"/>
If you like you can use it for the plugin.
Best regards
Lazinbee