When I went to EBSQ for the first time and saw dog art that done in small-format, I was not yet aware of things like ACEO and OSWOA. I just knew I was seeing some of the most wonderful small paintings of dogs I had ever seen, art obviously done by people who share their lives and hearts with dogs... I could really tell that this was so. It was "Art with Heart", most definitely!  I tracked down some of that art to its source.... eBay ACEO listings, and I was hooked! I started doing ACEO's and OSWOA's of horses and dogs. This after doing canvases for galleries as large as 50 by 65 inches! Quite a change for me.

It also gave me a new respect for the "small but important painting" concept.  And I learned a few things about what is and is not a miniature, and about off-eBay invitationals for miniature art (the kind where the paintings are examined under a manifying glass to see the quantity of brushstrokes).  

I am doing small paintings, still.  Not so many ACEO's now, because I need some minor eye surgery to help dry-eye syndrome, and new glasses. 

As for what does not constitute a miniature, one painting I am working on is of a baby bird, and is only about 3x3 inches. This is a tiny painting, but it is not a 'miniature' per se.... because the baby bird really is that size as depicted in this art.  So I will list it on eBay as  Small Format Art (SFA, an eBay group and designation I belong to) not as a miniature.

I do like that ACEO and OSWOA (and other post card size art and 3x5" art etc) are made to be sleevable for display albums. And they are wonderful for framing and hanging as a group.

My first serious oil painting was a landscape, and I had alot of menotrship as a landscape painter by the likes of  California "Eucalyptus School" Master, Karl Albert (who painted with Edgar Payne!) and workshops with my lifetime watercolor painting goddess, Nita Engle.  I taught myself to paint animals. I am about to do some bigger (but not too big) canvases of landscapes and seascapes, because I really feel like it.