Upload your image, copy bbcode full, paste in your message. You don't need to create account. I post a lot of pictures this way without any issues using my tablet. I just keep two tabs open and I switch back and forth. Saw you testing some in the testing gound. Try with https://imgbb.com and see if it works for you.
You are able to inline photos through Go Advanced as well.
You'll need to attach your photos onto the attachment manager.
Afterwards, click on the arrow beside the "paper clip" icon and you'll be able to inline the photos.
Here's my process. Start thread, Write what I want, manage attachments, choose, make sure it's 620x280 upload and then put up. When I click on on the arrow it brings up my attachment and when I click on that that it puts some script before my text and no picture. Sorry for being a pain.
if these are your personal photos you are trying to share, then first you must first upload them to a sharing site like the one lesblank mentioned.
click on the icon above the white area where you enter your text you wish to post. just above that is a box with a yellow sky and mountains and circle in the top right corner. click it, then insert the URL of your photo.
i'm moving this thread since it is not a technical issue with the site.