...the following will get you started with the most common ways:
First is to an individual post...
Choose the 'Go Advanced' button below instead of using the 'Post Quick Reply'. There you will have many more options with regards to formating your posts, adding links, etc. Type your message as normal, but before you post it, look in the 'Additional Options' section. You will see a section titled 'Attach Files' with a 'Manage Attachements' button. When you click that button, a new window will pop-up with the option to uplaod as many as 5 pictures with your post. For each picture you want to add, browse & locate it on your computer, then click on the 'upload' button. It will process the photos you have chosen. If they are too large, it will promt your to try again after resizing your images offline. Once you have uploaded your photo(s) then hit the 'Submit Reply' button below your post window.
The second photo option is to create your own gallery at the forum's sister-site airstreamphotos.com
Log in there using your same ID & Password as used here on the forums. Click on the 'My Gallery" button and then the 'Upload Photo' button and just follow the prompts from there. Again, try & keep your individual file size down, you'll be abble to post more photos that way.
Good luck...give it a try & see how it goes!