Thank you for getting back to us.
The option is now back in Sitefinity and if you upgrade your project to Sitefinity 6.3 you will be able to use it.
However there is a little bug because of which you can see the check box only for the first time when you add the image. If you forgot to check it or you want to uncheck it later you need to remove the image and add it again.
Unfortunately your second request for showing the image in lightbox is not yet implemented.
We are considering to implement it in the upcoming releases.
I don't know for sure if this can be achieved for Sitefinity 7.0.
In order to follow this feature request progress I logged a PITS Feature request and you can follow it here
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