If your using firefox for a browser it makes it alot easier. First you need to ctrl click add a new message at the top of this page. Second ctrl click share your pix. The two windows you keep open to copy and paste from the upload link and to add it to the message. You paste the code that is supplied after the upload is finished.

Then you click your back button to return to the upload page to add more images.

I don't know how clear that sounds but it took me a little while to become familiar with the procedure.

Firfox keeps handy tabs open to make it easier to move back and forth through pages.