How to get the epsa crop image in code

Hi there,

I am using quite complex template files in which I grab the image fields from the db and apply a format to them using something like this:

$default_thumb = image_style_url($THUMBNAIL_STYLE, $default_pic); // apply image size

However, if I use EPSA Crop and try and display any cropped image like this, it shows an empty black image.
How is this done correctly?