As a quick guide:
If you want your pictures to be the subjects of criticism - hopefully, of artistic criticism - then User Critiques is the principal envelope/place within which to post your images.
There is one section therein, Without Prejudice, started years ago, specifically to house pictures when for one reason or another, the photographers neither want not feel they need 'critique' from anyone else. That's not to say that the photographers are not open to discussion of their pictures, simply that they do not welcome the habit of second-guessing, which in the end (and if you think about it), is all that it, critique, can ever be and can also never be made devoid of a sense of (often misplaced) superiority...
Show us some Abstracts was started in order to make a space for abstract photography. Over the years, the interpretation of abstract, or should I say, the canvas the slot grew to accommodate it, has taken it far beyond any strict definition of the word abstract, to the point where almost anything that's not a straight, unmanipulated snap fits the bill. I feel that was a rather retrograde step, in that formula has stepped ever so sweetly into the fold, and any 'trick' is all it takes, whereas I had imagined - perhaps mistakenly - that abstraction was there at the conception of an image, not in later messing about. But that's digital for you!
If you don't want to place pictures within those pre-established spaces, you can simply post your own image by itself, creating your own title and adding whatever copy turns you on.
There are also other areas where photographs get posted, some of the best within the Medium Format section. If you are looking for professional work, that's where you will most likely find it.
To conclude: this is a wonderful site that is open, broad-minded (on the whole - faux politicians notwithstanding) and able to offer a regular user a lot of bang for his buck.
Rob C