Are you on your phone while accessing the forum Jezza?
I have an iPhone, but I’m sure it is not that different. When you are typing a post, there should be a little box under where the text is going in that says More options. If you tap that, you get a big box saying add a photo by dragging and dropping. If you scroll down to underneath this, there is a smaller button saying Choose File. Tap that and all the places your phone stores photos should pop up for you to choose from.
After that you just look through your pictures and tap the one you want and it adds it to your post. If you look at the preview it won’t show, but if you scroll down under the text input box, the photo should be listed in the attachments.
I have made this post on my phone and added a photo to test it