In this first picture, some kid is feeling up a naked lady. 
In this picture, some guy is on his back, waiting for his horse to consummate the marriage. 
Islam is born.
I hope this helps in your quest for art appreciation.
Note: I'm not an art appreciater, but at least I'm not stupid enough to say "That looks like crap" or "I could do that". I just don't "get" most art.
Art tends to break into three groups for me:
1. Stuff I just don't understand. Modern Art, Mondrian, Picasso, stuff like that. I don't know what I'm supposed to look at, or experience. I get nothin' (but at least I know I couldn't do that).
2. Stuff where I do understand and have endless questions I don't have any way of getting an answer to - "That's interesting. I wonder if the shark ate that lady, and why was she in the water anyway." "What happend to that kid? Were they poor, or did everyone live like that? What season was it? How many hours did they work? Why wasn't the kid in school? Did they even have a school? Could he read?"
3. Rubens, Renoir, guys who painted a significant amount of female nudes. Those I like 'cause I think the female body is beautiful, but somehow, maybe more is supposed to be going on there.
That's why I sort of like Dali, Man Ray, Duchamp, those guys. At least when I see a painting of a spoon or a bottle rack, I know what I'm looking at.
JRBC, what are your thoughts (and anyone else who doesn't feel the need to point out that I don't know anything about art. I already know that.)
Owl_Eagle
(If what I just wrote makes you sad or angry,
Some of what is going on is that these artists often are drawing from myth, legend and story you may not be familiar with..plus for religious figures in particular, there is an old tradition of certain figures being associated with certain symbols, like a fuller's club for St. James the lesser, musical instruments, especially the organ, with St. Cecelia, eyes with St. Lucy, and so on.
If you aren't getting some of it, it's probably because you need someone to give you not just an interesting picture, but the background to the subject to get the most out of it.
Those are good questions you ask. Sometimes, the background will give the answers, and sometimes, you are just supposed to wonder about it and come to your own conclusions, I believe.
I like Rembrandt and Vermeer a lot. Rembrandt runs from highly dramatic pieces like Nightwatch to a lot of really pleasant still lives, and lots and lots of portraits. Some of his best work though, revolves around his religious scenes, imho. Vermeer is beautiful, pleasant, skillful and relaxing to look at.
Rubens does do delightful, intimate pictures, but he does so many of the big pictures that you can study for hours they're so rich with detail and you often need to know the type of symbolism or background story behind it to get it all.
But re your point 1, knowledge of modern art, you might be interested in the previous "classes" I've done. These are all clickable on my home page.
class #10: Postmodernism http://www.freerepublic.com/focus/chat/1473061/posts?page=17
class #9: Pop and Minimal Art http://www.freerepublic.com/focus/chat/1470726/posts?page=2
class 8: Pollock and Abstract Expressionism: http://www.freerepublic.com/focus/f-chat/1468241/posts
class 7: American Modernism: http://www.freerepublic.com/focus/f-chat/1440373/posts
class 6: Surrealism: http://www.freerepublic.com/focus/f-chat/1427099/posts
class 5: Cubism: http://www.freerepublic.com/focus/f-chat/1427099/posts
class 4: Expressionism: http://www.freerepublic.com/focus/f-chat/1424087/posts
class 3: Cezanne and van Gogh; http://www.freerepublic.com/focus/f-chat/1419876/posts
class 2: Impressionism and Post-Impressionism; http://www.freerepublic.com/focus/f-chat/1414727/posts
class 1: Realism: Manet and Homer; http://www.freerepublic.com/focus/f-news/1410117/posts
A new series of art history "lectures" designed chronologically from Egyptian art onward:
Art Appreciation/Education series II class #1: Greco-Roman Realism and Early Christian Abstraction http://www.freerepublic.com/focus/f-chat/1491050/posts
Art Appreciation/Education Series II class #2: Romanesque and Gothic Art and Architecture http://www.freerepublic.com/focus/f-chat/1498966/posts
Art Appreciation/Education series II class #3: Art of the Renaissance http://www.freerepublic.com/focus/f-chat/1528015/posts
I have also begun a series on Visits to NYC and the art seen there:
Art Appreciation/Education: Visit to NYC I: Robert Smithson and James Turrell: http://www.freerepublic.com/focus/f-chat/1507874/posts
Blue Moon by John Haber: A review of Oscar Bluemner's retrospective at the Whitney (I wanted to write about Bluemner's work as my Visit to NY II, but I decided to post Haber's great article instead.) http://www.freerepublic.com/focus/f-chat/1507684/posts
Art Appreciation/Education: Visit to NY III: Elizabeth Murray: Return to Color and Energy http://www.freerepublic.com/focus/f-chat/1512127/posts
One other essay I wrote on Christo and his orange gates in NYC: http://www.freerepublic.com/focus/f-news/1348194/posts
You don't have to read them all! But maybe some will peak your interest. (I thought Millee might also be interested, just in case. Millee is now on the ping list.)
(I just hate to repeat myself from thread to thread, so that's why I list what I've already written.)
In this first picture, some kid is feeling up a naked lady.
In this picture, some guy is on his back, waiting for his horse to consummate the marriage.
Islam is born.
I hope this helps in your quest for art appreciation.