I have made this filter to be able to have collage of images that have a transparent background and so it can have random color squares as background
You can load also non-transparent images to make also collages with different square images.
Also you can use colorful square patterns without any photo overlaid
There are examples of all these in the presets.
The presets have a transparent background, but they are configured to use the main image loaded or anything configured in the main image menu