My question is this; how do I price my images for sale?

Is there a rule of thumb that I should be following?

for example, a full color poster having a size of 18 x 26 inches. printed on photo stock type paper, should sale for how much?

Here's just one of the images that I'll be selling: "Ms. Maddy Hatter"

http://excalibur.renderosity.com/mod/gallery/index.php?image_id=1239279

Start off from the cost of making the print. Total cost to the customer shouldn't be more than twice that. That's a general rule of thumb: if you were using a service such as Cafepress, you're paying them both for making the print and doing the order processing. And there's also a cost in having a stock of prints ready to mail. But the really obvious rule is to cover your costs: not just making the print, but the costs of postage and packing.

the straps and dress appear to be floating over the skin, as if they were pasted over the skin layer. maybe there's some way you can refine the shadows under the strap/dress edge. it might help sales a bit. then print 10 of 'em and set up yer sales page. customer pays shipping and taxes, so you mark 'em up 50% over cost, and see if anybody buys any.

Thanks for the tips and comments. There a large art show near me that I’m thinking about joining this year, and we’re only allowed 3 pieces for the show, but we are able to sell what we enter; that’s why I was asking about pricing my work.

if yer posting physical copies at an art show or gallery, then you frame 'em and ask the show director what the average price is for similar art that sells. that's the price you use. depending on the locale and income of the clients, anything from $25 to $250 above cost might sell, for an unknown artist. get some publicity of some kind for yourself (good or bad) prior to the show, and sales will increase.

I used to be an antique dealer as a hobby. An old dealer told me "Things are worth what someone else is wiling to pay for it" Good luck

Again, thank you all very much.