Several months ago, we found a faux oil painting that both Blake & I immediately loved, loved, loved! We had been looking at pictures for above our livingroom couch for a number of years and this one was IT. There was only two small problems. (1) The painting was not quite large enough to fill the space available (general rule: the picture/picture display above a couch should fill at least 2/3 of the wall space) and (2) We found the artwork at Marshalls (a discount store) & knew that finding a duplicate/corresponding image would be like searching for a needle in a haystack. Nevertheless, for the past several months we've looked at numerous stores without success & decided to come up with an alternate solution. ENTER: Hobby Lobby's 90% off home accents sale. Last night we found just what we needed for pennies on the dollar! Combining the painting (which, did I mention, we LOVE!) with randomly-sized photo frames, we were able to extend the size of the display above the couch while keeping the focus on the painting itself. For less than $100, ($70 for 3 foot-by-3-foot painting + $24 for frames), this is what the wall in our livingroom currently looks like. 
A simple solution for 'enlarging' a piece of artwork that is too small for its designated space.