posting pictures
Upload your picture to your profile, open your new topic in a new window, then drag the picture from there and drop it here.
Don't copy & paste - drag and drop. Open one window with the picture and another with the posting you're creating.
If you click on the picture on your profile, hold it down and drag it to the posting. You'll actually see the picture being dragged when you do that.
Copy and paste (ctrl v) work fine, you just need to make sure the photo is hosted on the internet, here, or Flickr, Photobucket, Facebook etc anywhere that is online and allows you to copy the picture. On photo hosting sites make sure you open up the image and are not trying to copy the thumbnail.
Good luck.