If the Images exist on the internet just give us the "address" of the image (from the URL bar of your web browser.
for instance: if i wanted to show you a futuristic imagining of a Merkava Tank i could give you this "link":
http://th01.deviantart.net/fs70/PRE/...v4-d3djelt.jpg
typing this (or copy paste) in your browser's address bar should get you to the picture
OR click on the "world and chain 'Link'" icon and paste it there to create a link in text like
THIS
If the images are only available on your computer then add them as attachments to your reply (go advanced button, scroll down, manage attachments, select file names, upload)