Hi WilltheBarb --
Basically, you need to find someplace online to keep your images for you, like
http://geocities.yahoo.com/ or
http://www.photobucket.com/ then register for web space and storage to hold your pictures online. When you've registered for space, then you'll need to upload your digital image files to that location. Once your images are uploaded and are on the Internet, then you're ready to post your images in the forum.
To post a picture to the forums, you need to click the icon in Guided Mode that looks like two mountains, one in front of the other, that has an 'Insert Image" caption. Up will pop a "script prompt" which has a single line text area to type in the 'address'/URL of the image, and the "http://" pops up automatically. For example, the "address"/URL for the image of the Idaho tang stamp is
http://www.geocities.com/geothorn/119SpecialIdaho.jpg
It looks like a link in the posting, and, if you'll click it, it'll take your Internet browser to the image, but that is also an example of the information that you'll need to post an image to the forum. If you want to test-post an image, you can feel free to use the "address"/URL listed above to try it out.
The biggest problem, as I see it, is talking you through registering at an Internet site, then uploading your images. I'd be happy to host your images on my web site so that you don't need to go through all of that, but if you can set up your own place to store your images, then you can post your images whenever and wherever, independently.
GeoThorn