Image description and opacity lightbox changing

Site URL: https://rayanevuillemin.squarespace.com/

Hi everyone,

I am new to this part of squarespace, I didn't even know we could code things. I have no experience whatsoever in coding, so I hope someone can help me figure this out.

I am making a new website for my photography, and I would like the following things for my website, but couldn't find any normal way to make it happen.

When one clicks on any of the pictures of my website, the lightbox appears. I would like to have picture descriptions that only appear when one clicks on the picture. I would like to add the name of each species of animal, and for it to be visible ONLY when in Lightbox mode, so that it doesn't mess with the regular page's layout. 
I would also like the Lightbox mode to be less transparent. I have found the setting and I pushed it to the less transparent it can be, but that's not enough in my opinion. Is it possible to code it so that it's almost entirely opaque?

If anyone can help, I'll be very grateful,

Thank you in advance

Rayane

Can you enable Gallery Caption & add some text first? We can check easier