A lot depends on the focus of the course.
When you get up to MA there are a whole host of things to look at.
Describing photographs.
Interpreting photographs.
Evaluating photographs.
You can look at types of photographs, context, ethics, aesthetics.
And others.
You can look at all of these from different viewpoints, too.
Realism, conventionalism, modernism, post-modernism, Marxism, feminism...
What you look at and the stance you look at it from depends upon the course you do and the preferences of the lecturers. Not to mention what is trendy*.
It can all be very complicated - and the language can be very difficult too.
The best place to start is by reading Susan Sontag's 'On Photography' and Roland Barthes' 'Camera Lucida' and take it from there.
* Currently it's the Structuralists. I prefer the Deconstructionist approach, myself.
Mmm... a better metaphor would be a blank canvas. We see what we want and we find what we look for.
Actualy that's a very flipant answer by me, but there is a fair bit of truth in it.
There is meaning in a photograph but it is open to lots of different interpretations. The problem is that people are still arguing about which is the correct interpretation.
Some people have tried to argue that all viewpoints are of value. This is true but it stands to reason that some viewpoints are of more value than others.
As I said, I veer towards Deconstructionist theory - embodied by the philosopher Derrida.
I just bought 'On Photography' and from what I've read in reviews, it seems to be a good book. A critical analysis of photography should be very interesting
There is a lot to disagree with in it, and she is a bit heavy on the adjectives - but it is a good read and will make you think.
Barthes is the same - and he is a 'must read' if you do an MA.