Do I have enough space to put 500 pictures on it?

Five hundred isn't a huge collection, as they go, but you've not mentioned the size of this group, though even with the free 5 GB iCloud storage plan they might fit. I'd suggest though that at least the 50 GB iCloud storage plan would suit your needs.

You won't be storing them on iCloud, they will be syncing from one of two possibilities.

You can use your Photos app to commence iCloud Photos syncing. See Setup and use iCloud Photos

If you have a Mac you can drop you collection into your iCloud folder and they will sync up to iCloud, but that isn't managing your collection as much as putting them somewhere for later.

Ringostar5 Said:

"Do I have enough space to put 500 pictures on it?: I wantTo know if I have enough space on my iCloud to store 500 pictures also I need to know how to do it thank you very much"

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All Seems Fine:

A high-resoltion photos would be 4MB max. With 1,000 Photos being 4GB(or thereabouts), 500 would be 2GB. So, yes, I'd expect you'd have enough space --whether high-resolution or not, and if there is lots of empty space left.