OK, let me assume that you uploaded the photo OK, and you should see a panel with some copy buttons with html stuff in each of the 3 windows. What happens next might depend on what browser you are using, but essentially you want to end up with the html stuff from the middle window of the three copied into your message.
The html stuff is the link to the photo hosting site for the image you have just uploaded.
So, first things - when you look at your message (use edit to do so) - do you have the html stuff copied in?
If not, then copying the link hasn't worked. Try either clicking on the Copy button (middle of the three), or just highlight the html stuff itself in the window, and use the right hand button on your mouse and then select copy, position your cursor in your text message where you want the image to appear, again right click on the mouse, and select paste.
If it is properly copied in, it should look somethng like
but without the * before the first url and the first img.
If your message does look OK, then let me know and we'll go back a step and check a few more things. This copying in is usually where things go wrong, it is a bit clumsy.