This isn't a get rich quick scheme, I'm not selling you an instructional booklet you have to buy for $19.95. But let me introduce you to Microstock photography. Many times for websites, advertising or whatever need, graphic designers, agencies, companies need photos. Its not always worth it for them to hire a photography and set up a shoot. A lot of times stock photos are purchased.
The designer goes a site, searches for photos that fits what they are looking for and buys them. The site money and the photographer gets a commission. Now, most likely your family portrait or snapshots are not going to generate much revenue or even be accepted by stock agencies. However if you spend a little time browsing through your photos, at least a few of the best might qualify and be suitable for stock. To take good stock photos firstly your images have to be well exposed, sharp and not too heavily processed. These let the designers do what they need to with the photos.
Your photos also must have stock value. So your family snapshots probably won't see their way into company X's next newsletter or packaging. Stock photos cannot have visible trademarks in them, and may also require a property release if a historic building is in it for example. You will also need a signed model release for every identifiable person in your photo. Most stock sites will have a model release you can download, and they will also usually accept generic ones from other sites as well.
What sells as stock? There are many thousands of images available of flowers and landscapes, so if your going to try and submit these, they had better be darn good. People photos sell, especially business people photos. People holding suit cases, in business meetings, group shots, medical professionals etc. Browse around at some of the micro stock sites I list below, most will have a popular images section where you can get a good idea of what you need. Most of these sites have a submission guideline as well, read through them.
Which sites should you sell at?
These are some of the sites I would suggest, you also support this site by signing up with the link I provide.
Fotolia
This is one of the first micro stock sites I started contributing to. It's also one of the ones I buy from as a designer. Their qualifications for submitting files is pretty good. They also provide good feedback as to why your images are declined, which is very helpful when starting out. They have good photo management tools and options as well as decent traffic, this is one of the more profitable micro stock sites.
Dreamstime
I've had an excellent amount of downloads from Dreamstime. Their approval process is also pretty good although the backend might not be as easy to navigate. They also pay out pretty good. I sell a few less photos, but each photo sells for more with Dreamstime.
123rf (formerly 123 Royalty Free)
123rf is a great site for buying photos, I actually use them as a designer. The reason is they have great subscription plans that let me buy photos without worrying how much they cost or what size to buy them at. While you don't get paid as much for a subscription download, people with subscriptions tend to download more photos. I used to just download photos randomly at the end of the day knowing those credits wouldn't be used anyways. Their management tools aren't as intuitive or easy to use, but they approve photos relatively quickly and it's a good site to start with.
Shutterstock
Shutterstock has great earning potential. Their submission standards might be a little higher than the above sites, so if you're having trouble getting your images into the above sites you might want to work on your micro stock photography a bit first. Once in with submitted images they have a great user base and have high earning potential.
Crestock
Crestock has been around for a while. Some people have done well with them, others haven't. They seem to be able to sell a few of my photos so I think it's worth the upload. Getting your photos on a number of quality sites is the key to success. All the sites I've listed are very reputable. The last thing you need is a site that goes out of business after a year, doesn't pay you, or doesn't count your downloads properly.