All good points. The lightbox will display the largest resolution for your display, which for me on my phone makes no difference for most images, on my laptop most images have a slight improvement, and on my external monitor a huge difference.
I am going to be adding in the ability to close the lightbox with the escape key, which I prefer doing, and maybe click off the image anywhere to close it too.
I have been working on the photo compression and image size optimization already and just thought that at the same time as working on that, I could get your opinion on the look and feel.
Also, your comment with the photo in has highlighted a new bug with the lightbox to me. If I click your image, mine opens in the lightbox 🤦♂️