How does Lightroom on an iPad handle Google Photos as a source?

Hi,

I just installed Lightroom on my iPad, and I'd like to use pictures stored in Google Photos as a source of images. My question is around how Lightroom handles the files. Does it sync the whole library to my iPad, or does it build thumbnails and only download the whole file when needed? Or does it work some other way? I don't have enough space on my iPad to hold everything, so if there's a smarter way to handle this, I'd appreciate the advice.

R