If you prefer to use a different design software (like Photoshop) but still want to showcase the full product list for your client to review, you can follow these steps:
Make sure your room rendering is saved as either a jpg, png or gif
Then upload the room rendering as you would a regular product (article: http://help.designfiles.co/managing-your-product-library/manually-upload-products-to-your-library)
In order to get the product list to display -- you'll still need to drag the product selections that were used in your rendering out onto the canvas. Don't worry about placement or layout of these products for now.
Once all of the products used in the rendering have been dragged out onto the canvas, drag your rendering image onto the canvas and ensure it's sitting "on-top" of all of the products you dragged out. If not, click the "To Top" icon in the left-side toolbar.
Once done... click [ Save ] and you should be good to go!