Go to somewhere that hosts pictures, for example; www.
http://photobucket.com Upload the pictures off your computer onto that website. There will then be an address below each picture, you can copy that address and paste it into a reply/ new message box so that others can click on the link to take them to the picture, or you can type [img ] before the address and [/img ] after.
This tells the forum that it's an image and will then display it as a picture rather than a web link.
Remember to take the spaces out of the square brackets I had to put them in there otherwise they wouldn't show up in this message.