Not a bug, by design. Php files are not accepted as embedded images. There is no such script as attachment.php here.
To show them:
Copy the attachment id from each url and paste it inside attach tag. So,
and displays in post as
You get the big image only in the original post where the attach id was uploaded. If you add the (hosted) photo to your gallery, you can use 'pick from gallery' tag to show it in full size in any post.
I hope this solves your dilemma.