You must first load them to a photo website, such as Photobucket. Once loaded there, open your bucket where the pictures are stored. Then when you place your mouse cursor on a picture, in the upper right corner a little gear icon will appear. Place your mouse cursor on that gear and a drop down menu appears. Click on the second line down that says share links. Then another menu appears, you want to click on the bottom line that says IMG code. When you click it, the word copied appears for a couple seconds. Leave photobucket open and come back to tradgang and in here where you type your message, right click then click paste and it pastes the url for the picture in here.
Clear as mud huh? LOL.. It's really pretty easy to do.