Brian, pics please, I would really like to see what you have there. Regardless, nice find for $100! I can only imagine that it has to be in pretty good shape being as it's only seen 2 winters of use.
Perhaps I can add to Gary's instructions above, If your taking the picture with your smartphone you can email it from your phone as an attachment to yourself on your PC. Yes your picture will have to be saved to your PC's picture file. To post it in the thread, select the "insert image" icon located on the left of the smiley face in the toolbar that appears within the thread you are posting, a drop down will appear, click within the box that drops down that says "insert image or click here". When you click within the box this will open a window for "this PC" where you can select the "pictures file", click on the picture you wish to insert. This will have to repeated for each picture you wish to attach to the thread. I hope that helps. If not, my apologies.