gunsmithandy, first you have to have you photos hosted on an outside service like Photobucket, ImageShack, etc. It is real easy for you to take them from your computer and put them on those free sites.
Then you get the pictures physical address, usually a right click on the picture will bring up the properties, and you cut copy it.
Once you have that, write your post, click on the little picture icon at the top of the message box, and paste in your address over the http:// that is highlighted. Always best to be in the advanced message section so you check the preview before you submit.