Currently you can add pictures to your post in all categories by going to the "Submit photos:" section of the form for submitting a New Ad.

This is located close to the bottom of the posting form.

You can add up to 3 images:

Click the first "Browse" button, then search through your computer's directory to locate your first image file. This will automatically load the file. Repeat this step for the second and third images, if necessary. Finish filling out all the required fields on the posting form and then click "Submit Ad" at the bottom of the page when you're finished.