How do I use Substance Painter Anchor Points in Costum Filter

In Substance Painter : If you use Filters like "Warp" you can get an empty "Image Input" Parameter where you can drag and drop Textures or use Anchor Points. 
I Want to make my own Filter in Substance Designer but I cant find the right way to use Anchor Points. What do I need to set up to get an empty image input field like in the picture?