Alternative to “Keep IMG SRC”

Hi, I have a few questions regarding the removal of the “Keep IMG SRC” option in future releases.

Since I’m currently using the “PictureFill” method with both “Keep IMG SRC” and “Lazy Retina” option enabled, I was wondering whether removal of the “Keep IMG SRC” would affect my site’s SEO. Without this option would the original images still be seen by search engines?

Also would enabling the “Lazy Retina” be a suitable alternative to the “Keep IMG SRC” in terms of SEO or would you recommend something else?

Thank you in advance.