I agree your images are dark, but your composition of them are good. I really like the ones with the spoons. I think instead of retaking a lot of them, it would help to use a photo editor like photoshop, but if you do not have that there are lots of free online editors. I believe this one is suppose to be a good one.
http://www.picmonkey.com/ I just tried it out to test drive it. It seems easy enough to use if photo editing is not your forte. I would say, try up loading a few and mess with the exposure to lighten them, make sure there is a good balance of contrast as well. I hope that helps!