Arrangement of thumbnails on screen, making collage

[ToranTarzan]

I have 4000 images that I have placed into 25 different folders. What I want to do is see thumbnails of the images from a particular folder visible on one area of my screen and be able to drag any of the individual thumbnails over to another section of the screen so I can put the images in specific arrangements.

I do not need to edit the images because I have already done this in Adobe Photoshop. I just need to make collages on one side of my screen from a bunch of thumbnails shown on the other side of the screen.

How am I able to do this?