Welcome to the community and thanks for posting, @Martin_Egsdal!
Currently, the closest thing you could do would be to use a transparent tile color. The tiles have a slight shadow effect around them which would leave a bit of a bordered tile look, so I understand that this wouldn’t exactly accomplish what you are looking for, but I wanted to throw it out there as an option.
Can you clarify how you would expect to use images instead of tiles? Do you mean completely replace the tile with an image? Including dropping the icon, label, footer, etc. and replace it with an image?
My intend is to use a 3D model of my appartment I have as a background image, and then “anitmate” an “icon” for each smart device I have in the location it is on the “background image”