Q: How can I be sure my photos are archived on iCloud so I can safely delete them to free space on my iPad?

I am travelling currently and my iPad is now at capacity.  This being the case, I purchased 50GB iCloud storage so that I can safely store my photos on iCloud and delete them from my device. i have ensured all the settings are correct to execute this but want to make sure they are all on iCloud before I delete from my device. How can I see the photos to make sure they are there and, if they aren't there how do I get them there? Encouragingly, my icloud storage is down to 30.8 GB from th 50GB I paid for But I would like to check I can view the photos from say, my iPhone to make certain they are on iCloud before I delete anything.

I have tried iCloud.com but it gives me three options; set up iCloud on this device, open find my iphone, open find my friends. It doesn't give me any options to sign in and view files/photos.

I Have also tried downloading the iCloud Drive app, but the app shows no items (Although im fairly sure this app is for files not photos)

thanks in advance!