I think waht happens is that by clicking on the link thing in the gallery, you import a space which messes up the coding.
What I do is to right click the picture, choose "Properties" in the bottom of hte box then tripple click the address and right click that, choosing the "Copy" option.
Back in the post, I clilck the IMG button, highlight the text not in the brackets, right click this and choise the "Paste" option.
If I'm doing multilpe pictures, I'll drop the addresses in a word document first, add the image tags, img and /img inside brackets at the beginnig and end of each address and copy and paste the whole thing into a post.