I've been using Google+ for free automatic backups of my iPhone photos. It's not perfect, but if you can live with its limitations — the main one being that photo size for a free plan is limited to 2048x2048px — then it's pretty amazing. Seamless, unlimited and free is just what the doctor ordered for me personally since, honestly, most of the photos I take I don't really look at ever again.
Today there's one more reason to use Google+ for photo backups, at least if you use Gmail, which I certainly do. Starting today you can insert photos directly from your Google+ backup into emails composed with the Gmail web browser client. It works great, and it's definitely one of those things I'd been thinking, "Why can't I do this?" about. Well, now I can, and I'm pretty pleased about it.
They say that Google is rolling the feature out gradually throughout the day, so it may not appear instantly for everyone. For me, I was able to get access to it by simply reloading my Gmail page.