Option 1 is to link to the website that contains your photos. When you are viewing your photosite, it’s specific address will show in the address bar at the top of your browser. Left click on this address and it will turn blue. Then Right click on the address and select "COPY" from the dropdown. Now, you can go to the Garden Web site, pull up the "New Post" or "Reply" window, which ever is appropriate. Position the cursor in the box that says "Optional Link URL". Then Right click and select "PASTE". This inserts the link to your pics. Then drop down to the "Name of link" box and give it a descriptive name of your choice. You then can type your message or description in the message box.

Option 2 is to embed a picture directly in your message. Note: some photo sites will NOT allow photos to be embedded here. Webshots is one that won't work. Photobucket works very well.
This gets a little tricky but is really simple if you’re using Photobucket. When using photo bucket, there will be three lines with addresses under each pic.
Left click on the one that says TAG and it will turn blue.
Then Right click on it and select (L-click)"COPY" from the dropdown.
Now go to the message window on the forum, position the cursor in the message window and R-click and select "PASTE"
This will paste that tag line in the message window. Your pic will show up when you select "review".
Now, if the photo is pretty big you might want to resize it.
In the tag line that's showing in the message window add this between the last " and >
width="300"
now the end of the tag line will look like this .....jpg"width="300">
300 is an arbitrary number. If the original pic is say 800 x 400 then 800 is the width. To down size the pic by 50% then use 400 for the width.

There is a test forum at the bottom of the forum page. You can try out stuff there. Good luck.