[member="Lady Kay"], when you are posting, on the computer, look at the two rows of icons. In the bottom row just under the smiley face, and the font color, is a little picture icon. Click on it, and paste the URL of the picture you want into the box, then press okay. The picture will show up, and you are good to go.
Otherwise, if you need a place to put a picture on, you can use photobucket, tineye, or other like minded sites to put it onto the interwebs.
*and the url of the image is literally a page with only the image. TO get that, you need to right click, and select open image in new tab.