I use Flickr and here's how it works:

Click on your image. You should see a set of four icons at lower right, one of which is an outline of an arrow. If you hover on it, it will say 'share photo.' Click that.

You should now see a window with four share options. Select the one that says BBCode (that's usually the default for me). You should now have a link displayed, or you can choose the photo size to alter the link. Once you have done that, copy the link.

Paste that link directly into the BF 'reply to thread' window. Do not use the 'insert photo' icon.

That's it. Works for me anyway. I know that allegedly one can post directly from saved files without using a 3rd party host site. I can't say whether or not that works at all, but the one time I tried it from my phone, no dice. I just tested the above method from a desktop and it worked fine.

Would love to see pics of the TC/CT. Lots of fans around here.