mangiaphoto

If you have cool digital photos, you may be able to make a little extra cash by selling them online. For this you need to be image owner and you need to choose good stock agencies for selling your images. You can choose more than one stock agencies. This won’t make you rich beyond your wildest imaginations, but it can nicely supplement your income. Usually you only get to keep 20% or more of the proceeds when signing a contract, but realize how much time you will sell your image and how much money these companies are spending in advertisements. Before contacting an agency, first get a feel of what types of photos they sell. Also, make sure your photos are in the correct format, both resolution and image format (TIF, JPG, etc.). If possible, and if you are not forced to sign a non-exclusive contract, register yourself on more than one stock agency to sell. For more information, here is a comparison about you earnings on stock agencies.

Shutterstock

Shutterstock is different than other stock models. Buyers subscribe on a monthly basis and can download up to 750 images over the course of 30 days. Shutterstock will pay you 25 cents every time one of your images is downloaded. Their subscription model encourages buyers to download a greater volume of images than they would at most other agencies. Current Payout $0.25 (US) per download. That means that at just 2000 downloads/month, you can earn $500 (US) per month!
I like Shutterstock but if don’t want to sell your images for 0.25$ you should know that this stock agency is favorite in micro stock world. For example I have 140 images in my gallery and I earn about 1.5$ per day. Imagine that you have 1000 or more stock images.

File size must be at least 4.0MP. They accept JPG and TIFF images. Also they accept vectors and footage.
Model release required for images with recognizable human facesbut ShutterStock does accept editorial photos (newsworthy photos without a release).
Payout - monthly, but you must accumulate at least $75 to be paid. All earnings are brought forward into the next pay period until you reach $75, at which time a payout will be issued automatically. The default minimum payout is set to $100 and you can change it to $75 if you would like. They support checks (slow and hard way), Paypal and Moneybookers (good option if you are from Eastern Europe or from countries unsupported by Paypal).

iStockphoto

The royalty structure on iStockphoto is 20%. If you are eligible for exclusivity, you can make up to 40%. iStockphoto sells your images starting on 1$ and up (depending on image size). Mostly, you will sell small or medium images and you will earn 0.20$ or 0.60$. Only problem with iStock is upload over HTTP (FTP is not supported) and week limit (20 images per week). Bellow you can find more about iStockphoto and prices:

You need 500 downloads to qualify.
Payout - by request , but you must accumulate at least $100 to be paid. All earnings are brought forward into the next pay period. They support checks (slow and hard way), Paypal and Moneybookers (good option if you are from Eastern Europe or from countries unsupported by Paypal)
They don’t support FTP upload (only HTTP or by Imagemagic software). Week limit is 20 images (bad ). iStock accepts RGB, JPG files only. TIF’s, PNG’s, PSD’s will be declined. CMYK images will also be declined. When uploading Vector files, one (max) 270×270 preview/thumbnail JPG is required. The source file for Vector/Illustration files must be a zipped EPS or AI file. They suport flash files (zipped SWF & FLA). Minimum image size is 1600×1200 (2Mpix).

Dreamstime

On Dreamstime you will get 50-65% ($0.50 and up per image) from each sale you make. It depends on image level and size. Also if you want to submit image to assignment, you can’t submit image to another stock agency. If they accept your image to assignment, you can choose to escalate your image to level 2 or to sell image rights (you get 25$).
Images must be at least 3MP in size, JPG, highest quality. Model release required for images with recognizable human faces.
Payout - monthly, but you must accumulate at least $100 to be paid. All earnings are brought forward into the next pay period. They support checks (slow and hard way), Paypal and Moneybookers (good option if you are from Eastern Europe or from countries unsupported by Paypal).

Featurepics

Featurepics is an Internet tool for the realization of the free market; where an Artist is responsible for a product and supervises its price, and a Buyer completes this market by buying the Art. you can set your own photo price - and when your pictures sell you get 70% of that price! There is no need to categorize your images when you submit them here. FTP makes upload easy. Only problem here is to set good image price. You decide, but be careful because you can repel buyers with expensive images. Before you set price, read image prices on another stock sites. Also, on Featurepics you can choose several image licenses.
Payout - monthly, but you must accumulate at least $50 to be paid. All earnings are brought forward into the next pay period. They support checks (slow and hard way), Paypal and Moneybookers (good option if you are from Eastern Europe or from countries unsupported by Paypal). Short dimension for Images should be not less than 600 pixels in JPG format.

Fotolia

Only an image may be exclusive with Fotolia not the photographer. A photographer may choose to sell photos with Fotolia on an exclusive or non-exclusive basis.
When a photographer chooses to sell an image exclusively through Fotolia, the minimum commission earned is 50% of the sales price.The photographer may earn additional commission depending on the photographers rank.
When a photographer chooses to sell an image non-exclusively through Fotolia, the minimum commission earned is 33% of the sales price. The photographer may earn additional commission depending on the photographers rank.
Files must be at least 1600 x 1200 (2 million pixels) and less than 20 Mega bytes. JPG format. Model release required for images with recognizable human faces.
Payout - monthly, but you must accumulate at least $100 to be paid. All earnings are brought forward into the next pay period. They support checks (slow and hard way), Paypal and Moneybookers (good option if you are from Eastern Europe or from countries unsupported by Paypal).