The they will have a url. Copy and past that url into the photo url box. The photo will show up when folks click on your ad post.

You can reply to your ad to post a photo. To edit your ad you have 4 hours where the Edit post button shows at the bottom of your ad. Click it and do what you need then click submit. After the 4 hours you can't edit. But you can reply to your ad to give more information and as I said before post pictures.

Search "posting pictures" or "imagecoast" etc.  

One recent thread is linked below. Read the explanation.

Your personal computer and personal phone store pictures but they are not "servers" for public access, so those urls won't work. (C:\Users\Colleen\MyPictures\.......  THAT WON'T WORK!)

In the meantime, I copied the URL of one of your ad pictures. This one:
http://img.adultsearch.com/classifieds/868007_rpD6DFDIedlo9L9uhJeg.jpg
Obviously, that pic is stored with public access (to VIEW, not to edit or delete) on adultsearch.com so I will paste that URL in the  "picture URL" box like this, making sure that there is only one http://

picture URL [http://img.adultsearch.com/classifieds/868007_rpD6DFDIedlo9L9uhJeg.jpg]

For more flexibility and control, create a free account on imagecoast or similar and upload your picture to there. Then you can use those URLs in future posts.