Whatever, one of the way of sharing your work of art, or doing something with it, is to put them at some Photo host (as an example) or enter various contests etc..
As the creator of something art, you're owning the copyright to that piece.. The laws are slightly different depending on what kind of media it is.. As in, what falls under copyright laws, as well as how long they're protected etc.
What that means, is that you, alone can decide what to do with images. You have the right to display them, you have the right to decide if someone else can use them (for free or for money), and setting up exactly how they can use the images etc.. If, say.. company X happens to like a certain image of mine, and wants to use it on the cover of a major novel, I can say.. Yes.. If I get ¢10, for each copy of the novel (as in.. if they're printing 100,000 copies of that novel, with that cover, I get $10,000) + a certain sum, say $2,000 for use in advertising of the novel (showing the cover).. a total of $12,000). That, of course, limits the way that companie can use my image.. They don't get the copyright, as such.. only the right to use the image in a way that the deal specifies, and in no other way.
You can always sell it in a not limited way as well, when someone can use the image as they like, as long as they doesn't sell it to someone else.. But.. they can.. if they see fit, print posters of it one day.. and a week later, use it to print a calendar or whatever way they want to use the image.
Then, you could always sell the copyright, in a more direct form. Then, the company buying the picture, has exactly the same copyright as I had..
If you read the fine print of contests or certain photo hosts etc, they often say that everything you give them, they've got the right to use as they see fit.
If you submit an image to a contest, it's often stated that the magazine, Kodak/Fujifilm or whoever is arranging the contest, has the right to use the image. You don't even have to win anything etc.. as long as you're submitting an image, they've got the right to put it up on their site as an example of images, to use in advertising, print in magazines or whatever, without you getting a single cent for it.. Basically, you're selling away the rights to use the picture, without getting any money for it, and in some cases.. you even have to pay an entry-fee, for the privlige of giving them the right to use the image..
Was just reading this text on a site, in "Site Policies"..
"While you will retain ownership of the copyright or license in the content posted by you, you agree that all content posted by you shall become part of a database in the Site, and that XXXX will own the database and copyright in any derivative works based on the content. In addition, you warrant that all so-called moral rights in those materials have been waived. Neither XXXX, XxxXxxx nor any third party using the content in accordance with this section will be obligated to pay you any royalties or other compensation for use of the content."
Which, as far as I understand it, is that.. every single file I'm uploading to that site, is owned by them, and they, or whatever partner they're working with, can use it in any way they can think of, and you can't do a thing about it, and don't get any money at all..
The scary thing, is that such a lot of people/artists isn't aware of this fact.. (I wonder how many even reads the fine print..