I would suggest something like this... keep it very open and light. Nothing solid backed sizing and style would be based on the space available and you taste or course.

I would also suggest keeping it white (or close to it)

You may also want to consider a new layout for the rest of the room to make it seem larger :) Good luck!

Definitely put the chair back into the dining room instead of in the corner where it is now. It is too crowded for a chair. A shelving unit like those shown above, or a credenza with drawers or cabinet space that isn't very deep, and your framed art hung above it instead of high on the wall where it is now. Are the couch & 2 chairs facing a tv? That may explain the angle the chairs are on.

No sense getting something that is going to be filled with tchotchkes. You might want to look for something that fills about 3/4 of the length of the wall there, but shallow. Does the couch look at this wall? If your TV does not have storage below, that might be a better spot for a storage piece. Can you add more photos of the rest of this room to your next comment?

You mentioned the high ceilings, pretend they are not! Bring your art down to human scale. The larger pieces above the sofa need to be lowered, starting down about 6 inches above the sofa. The small frames would be better together and stacked, or side by side, not staggered. The only art that looks ok high up are very large rooms with very large art viewed from a distance.

Here's a rough idea of something simple you can do to reorganize your walls. If you wish.

I would add a larger piece of art, in this case a clock, something light, that won't pull too much attention.

I tried to reuse the rough sizes of your pieces and used your shelves (I'm not sure if they can hold books) but would be a nice addition to balance the space with a small vase or similar item. I also would suggest getting lamps that are the same size - or at least have the same size shades and finished heights. Currently making your space off balance.

I might also make the right side wall kind of a gallery to put as many or as few pictures as you wish. Just be sure to balance your frames so it all flows :) This will make your eye settle on the 'clock' or other art piece.

Good Luck!