These days many stock photo libraries offer video and music as well as stills. Above is a link to an account I've just set up with Pond5. For the most part I shall be uploading music tracks to this library, as it takes a long while to get enough images and video uploaded to start earning enough to justify all the work and I already have libraries that perform well for me that I concentrate on.
So, if you are interested in selling your creative output, what's the best way to start? Well my advice would be to look around and see which libraries you think are the 'best fit'. I have varying degrees of sales results with the various websites I upload to and that may well not be the same for anybody else. It's obviously a good idea to upload to a few libraries that look promising and see what kind of results you get. However there is a problem with that. Firstly you need a reasonable amount to stand a good chance of making some money and secondly it takes a while to get an idea of how your work is selling.
If you are looking for some figures on this I would suggest that you need at least 1000 images online per library and it could be a year before you start to get an idea of whether that library works for you. As you might imagine from this, patience is a virtue in the stock world and unless you are blessed with a talent for creating commercial work and / or have access to wonderful locations and models in the case of stills and video, you may well feel dispirited with the lack of financial return in the early days.
BUT!! - If you are able to successfully produce a variety of creative styles, you enjoy doing it anyway, you have another source of income and you are in it for the long haul it can be a rewarding (in all senses) experience. It did take me a while before I was able to make 100% of my income doing this and while I live 'comfortably' any notion of getting seriously rich isn't something I anticipate.
If you click on the screen shot above you will link to the site of the worlds best selling stock photographer. 1,000,000+ images sold every year. Now this guy is a workaholic and deserves every bit of his success. Some of you who are contemplating a career in stock may be inspired by him, some may fell intimidated and give up any notion of pursuing this. However, the experience of myself and many of my stock shooting colleagues isn't quite so pressured or ambitious. As I've mentioned many times I sell between 15-20,000 units of creative output per year. Mostly photographic still images but my music and video sales are rising. I've joined my own million dollar club in that I have total sales of over $1,000,000 since I started creating stock. Yes, I work hard at it, but since it's something I love doing I don't find it a hardship. And that really is the key to it. And no, editing, captioning and key wording isn't my idea of a good time, but these days there are fairly painless ways of doing that.
So if you are a committed photographer and have a pretty large stock of images, then this may well be for you. Just don't expect to upload a few images and expect the money to come rolling in. But if you are prepared to commit some time and energy to it, you may well find you get your rewards. Not much different to anything else in life really.
N.B. If you want to have a look at the top stock libraries and get some idea of what I sell have a look at my http://www.soundimageplus.com/stock-photography/ page.