Is a Stock Photographer an Artist?

When I first started taking photographs, I never fancied myself an artist.  I just enjoyed the feeling of being behind a camera.  Looking through the viewfinder completely changes the way you see the world--you pay more attention to the colors in the evening sky, the way a shadow falls across an otherwise ordinary object, the way kneeling down to look up at an object can suddenly make it feel so much more imposing and powerful.  Now, I still don't jump to label myself as an artist; I'm a bit worried that self-labeling may open the door to pretentiousness and hubris, and I'm the first to acknowledge that I'm largely a self-trained amateur, with the exception of one photography class in high school.  I'm fully aware that I have yet to prove myself.  Still, I've come to recognize that my photographs (at least some of them--probably not my endless catalog of every cup of coffee I've ever consumed or cake I've baked) are enjoyable to a broader audience than just myself.  I've also realized that living in Europe isn't cheap, and a girl's got to eat!  So, I started reading some tips on becoming a serious photographer and getting your work out into the public eye.  In addition to opening an online gallery (here) and asking local businesses to place your prints on display, the resources I read also suggested selling images to stock photography websites in order to gain name recognition.  I've heeded this advice and submitted a portfolio to a stock photography site, but, while my portfolio has been approved, I have my doubts about how sage this advice actually is.  Now, perhaps I've simply chosen the wrong site for my stock photos, but it seems that the prices offered for the photographs are far below what I could expect to earn selling the images independently--especially once the steep commission the website collects is taken into account.  More fundamentally, I wonder about the artistic implications.  I'm required to sell the photos exclusively on the website, and I find myself selecting less artistic photographs because I'd prefer to display those in my personal gallery. 

So, if the point of selling the stock images is to promote my work (stock photography doesn't look particularly lucrative so far), am I selling myself short by refusing to post the work I'm proudest of so that I can display it in my personal gallery?  What name am I making for myself by selling images of wedding cakes and cappuccinos?  Beyond that, the site editors review each individual piece posted, and reject photos which a) are not aesthetically or technically adequate, b) are not well-composed, or c) do not provide utility for potential buyers.  Of course art is subject to critical feedback, and I accept that I may face rejection and harsh feedback.  The point of such criticism, to me at least, is to push my photography past my current limits--to allow me to view my work from a different perspective, and to improve in areas that need to be addressed.  However, because 1) I am not displaying my best work and 2) the feedback provided simply states that rejected photos do not meet one or more of the requirements (without specifying which requirement), the utility of the feedback provided in such forums is limited at best.  Should I be concerned that the composition of the photograph is substandard?  Are there technical and aesthetic errors I should be made aware of?  Or is the site simply flooded with too many photos of butterflies and flowers?  So, I ask you sincerely--is a stock photographer an artist?  Is there untapped potential for artistic growth in the stock photo industry?  Below are a few of the images that have been accepted, interspersed with a few that have been rejected.  Perhaps I'm missing something here--can you tell which were rejected?  Constructive feedback is genuinely appreciated...