If you are trying to do all this with a tablet, just give this one more go.
Mine's a samsung, but I'm sure the ipad works the same way.
Get your image up on screen.
Put your finger on the image and hold it there until an options box opens up to the side.
One option should be something like "view image".
Touch that option and the image should open up on its own, with the written code details above (normally ends in .jpg)
Copy that entire code (by pressing finger on code so it all turns blue and then pressing the "copy" option box.
Bring that copied code here and paste it into the reply box so you can post it.
To paste it, simply go to the blinking cursor in the reply box and press your finger on it until the paste option shows.
Before actually posting, put [Img] at the beginning (no gap between the bracket and code, and [/img] at the end, again with no gap between bracket and code.
Worth a try....