I'm not a moderator here but here's the process. Store you photos on a photo hosting site on the web. There are several free ones out there. Make sure they allow direct linking. Many do not any longer. Upload your photos from your computer to these sites.

Some to check out are snapfish.com, hunt101.com, phototbucket.com.

Then simply copy the url to your photo and click the image button at the top of the text box when post a reply and paste the url between the formatting brackets.

See if it works with a picture of my daughter and a doe she shot.