if you do not draw a room you cannot add a floor, right ?

Yes. Automatic floor generation may appear in a future version, but if it could be handy in many cases, I fear it could get worse for special cases like mezzanine, multiple floor in a room...

Thank you, is it possible to delete the area measurement that appears when you draw a room ?

how do you create an image file (*.png, .jpg, ecc.) of the floor plan

You can export the plan at SVG format with the Plan > Export to SVG format menu item, and you can get a bitmap image of the selected plan items with a copy/paste in any image or word processing software (this second solution might not work under Linux).[/quote]

Thank you, it would be nice to have a simple save as image file though.