How to set 'alt' and 'title' attribute of <img> tag rendered locally for SEO purpose?

[ChiragMoradiya]

I am writing a website using Polymer. It is using some images on almost all pages. All images are rendered using tag.

In order to provide proper HTML content to Search engine bots, we are going to setup Prerender.io proxy.

But, I think that won't be sufficient in case of images. As, using won't set 'alt' and 'title' attribute of rendered as local dom.

So, I request you to add support for those 2 attributes.

[bicknellr]

alt is available, title isn't though.