As a generic rule of thumb, I would size it at 3' tall. That is assuming you have a table that is 30" tall, leaving 60" between the top of the table and the ceiling. If you hang it so that the bottom of the picture is 12" above the table and the top of the picture is 12" from the ceiling, the center of the picture will be at eye level (usually around 5' or 5'-6" above the floor).

However, depending on the total size of the room and all the other stuff you have in the room, and depending on the width of the photo, this might look too small. Try cutting out pieces of cardboard at various sizes to see what feels right.

If you want something super bold and dramatic, have the photo printed onto vinyl wallpaper and cover the entire wall!

This is just about what I have now. I was wanting to go BIGGER (taller). To me, the wall looks too bare. Thanks though, it's always good to have other opinions. I wanted the the vinyl wallpaper but I have knockdown textured walls.

I think you hang an artwork that is 12" - 18" from the ceiling and 24" from the floor and 18" - 24" from the side walls. (going with 12" from the ceiling, 24" from the floor, and 12" from the side walls = 66" x 38" ) or other option is Approx. 54" x 54". It can come down into the wall lower than a dining table height, as long as it won't get damaged by people getting in and out of a chair. It might feel like it may close in on you if it's very large.

excellent idea. thanks