Your screenshot doesn't show and you don't mention what the error message was.
When you upload an image here, a link to the uploaded image is inserted in your message so that it will show when people read your message.
To give it another try: reply to this message, press the Upload button, press Browse to select the image on your system, press Upload to transfer it to the forum server and to have it inserted into your message.
Hopefully when you do this, someone will know how to solve the problem.