1) Artwork hung way too high
The Pretty Organizer has a great post about how high you should hang your artwork, along with pictures to illustrate - click on over there.
The 54-inches-from-floor is a general rule of thumb. Rules can be broken; if you have a particularly large piece of artwork or grouping, feel free to hang it lower so that the top of it isn't too high.
The second mistake is:
2) Artwork too small for the space on the wall
The rule of thumb is that the artwork should relate to the item of furniture it is hung over. If the centre of the artwork is 54 inches from the floor and the piece of furniture is low, the artwork will need to be bigger (or a grouping of smaller art) so that it doesn't look like it's randomly floating above the piece of furniture.
Here are some pictures I made to illustrate:
Okay the first picture shows mistake 1 and 2 - the artwork is way too small and hung too high. It is randomly floating above the furniture, makes you crane your neck up to look at it and it is too small so you have to come right to it to appreciate the picture.
Aah, much better! You see, my former clients, I wasn't trying to upsell the size to make more money, but so that your portraits would look better in the spaces you wanted to hang them.
Okay this one isn't too bad, right? Artwork is nice and big, the width is appropriate for the furniture ... but hung at the correct height there is still too much of a gap beneath it. (Now, this gap would be fine if you were planning on putting a lamp or candlesticks or other taller items on the chest, to lead your eye up, but for the purpose of this illustration we'll assume the furniture will be as-is.)
See, by going smaller with the artwork you are able to group two together to create the appropriate size.
Hope this has been helpful! Now go and fix your artwork!
