Imgur works well if you need somewhere to store and host photos, and is free https://imgur.com/ just click on the photo and copy and paste the bb code.
The picture I recently added of my valve cover was uploaded directly from my phone (android) with no problems. I used to get that message a while back, so I would text myself the picture, then download the one I received, and upload that. That is just kinda a cheat to compress the file a bit.
im still having trouble trying to get it to work lol and tried sending them to myself as well no luck on the iphone