There are several ways to post a photo. The way you choose to post a photo depends on how you choose to interface with the forum. Many posters here don't realize there are several different ways to interface the forum and forget that others may be interacting with the forum in different ways. Many posters interface with the forum over their email client. When you typed that post and posted it, it popped up as an email in a lot of people's inboxes. Any of those people can reply all to that email and depending on the details of their email client, can attach a photo. That's one way to attach a photo. Lots of people, myself included have emails 100% turned off. Others only interact over email.
Many people interact with the forum via a webpage on their Desktop PC. That interface has a paperclip for attaching files, and a photo thumbnail button for attaching photos. That's a second way.
Many people interact with the forum via a stripped down mobile webpage interface on their phone. There is no obvious way to attach a photo that I know of, and on my phone (iphone and Safari) I can't even post or respond to a post directly. If I'm out on the road reading the forum on my phone, and I think I may want to chime in, I click the "subscribe" box at the top of the thread, and that causes any post to that thread to hit my email inbox. Then I reply all to that email.
Some people toggle their phone from the mobile view to the desktop view to get more features if they need it.
I tend to put my photos on my flickr and never post photos, but instead post links to photos, along with a few words describing what this photo-link will show you. That's another way.
Bill Lindsay
El Cerrito, CA