Add imageSize as an input so it can be used in lightbox mode

[MurhafSousli]

No description provided.

[aardvark79]

This feature does not appear to be working correctly in version 3.1.1. Setting the imageSize input to "contain" does not have any effect.

[MurhafSousli]

@aardvark79 because the default value of imageSize is contain :)

[aardvark79]

I may be missing something, but I've tried both 'cover' and 'contain' and both settings have a 'cover' effect - there doesn't appear to be any change regardless of the value used. Like I said I could be missing something, though. I'll try to set up a stackblitz in the morning.