Not a stupid question and I curse anybody who would think otherwise and call you names like "newbie"
First post your picture to a site such as photobucket.com
Save the url as a link (control-C)
There icons at top of the section wher you posted your message on this site.
If you click on the icon that looks like a picture frame the following will show up.
Paste the url link (control -v) between the brackets
hope that helps if imissed anything Im sure somebody else would help