Tech-challenged inserting photos

Hi All,
I'm thinking of selling my scope and wondering how does one insert photos in classifieds? When I clicked on the "insert image" icon, it took me to "Enter the URL of the image". DUH?
I have a Sony cyber-shot digital. Please enlighten me with an Insert for Dummies version.

Thanks....Gloria

Practically speaking, that means--"tell me where the image is on your hard drive."

Assuming you have loaded an image of the scope in your computer, just use the "browse" feature on that screen to go click on the image.

Alex