Hi Almo,
Thanks for reaching out to us! Basically everything is still the same with the new editor (and you can still access our old editor here). To overlay an image you simply expand the Photo Basket (at the bottom of the editor) and drag it on. To then erase from it you still use the Erase button on the Photo Properties dialog, however it looks a little different. You can find it just above the DELETE button at the bottom of the dialog (to the right of Flip).
Let us know if you have any other questions.
Regards – The Ribbet Team