You can use this to generate multiple "random" images from "layers" you've created. For example, you create multiple PNG images of backgrounds, store all of them in a folder called "1-background". Then create multiple images of an item you want to be on the image, store them in a folder called "2-nameofyouritem". Each folder is a "layer" and the images inside are all the posible layers the program can use. You can add as many images as you want inside a "layer" folder and add as many "layers" as you want but at the end only 1 image from each folder will be used to generate the final image. The images are generated by choosing(with a probability you choose from the sliders that appear after you select a folder containing all the "layer" folders) 1 image from each "layer" in the order they appear in the list on the left, so it's important that you name the folders correctly(that is, by appending a number to the name of the folder that contains the images, in this format "numberoforder-nameoflayer") in the order you want them to be "stacked".
Folder structure example:
├── yourinputfolder
| ├── 1-background
│ | ├── nameofyourbackground1.png
│ | ├── nameofyourbackground2.png
│ | ├── nameofyourbackground3.png
│ | └── ...
├── 2-item
│ | ├── nameofyouritem1.png
│ | ├── nameofyouritem2.png
│ | └── ...
├── 3-item
│ | ├── nameofyouritem1.png
│ | ├── nameofyouritem2.png
│ | ├── nameofyouritem3.png
│ | ├── nameofyouritem4.png
│ | └── ...
├── 4-item
│ | ├── nameofyouritem1.png
│ | ├── nameofyouritem2.png
│ | └── ...
└── ...
