So, this image when Edward is putting Elizabeth Masen's on Bella's ring finger is from this pic of them in the meadow towards the end, as in the book and the leaked script, lol. No spoilers there right?
Notice Edward's shirt...
...and not during this time, when Edward proposed to her.
Thanks Anon. We cannot tell if Bella is wearing the engagement ring here, but she is wearing her moonstone ring on her right hand and holding the engagement ring box. As we all know she kept the ring and didn't wear it until the end of the book, when they decided that it's time to tell Charlie.