The only way to open an image file in AnyRail is to first create a workspace the size of the layout in the image. Then create a rectangle (right-click and choose Line/Surface). Click on the frame of the rectangle and in the ribbon bar choose Load Image. You may need to monkey around with the image proportions to make it fit the space precisely.
Remember, AnyRail is not Photoshop. It was not designed to work with images except as background elements. It is a planning tool first and foremost.
(P.S. I sent you the native AnyRail file for the plan in question.)