Trouble getting all pictures to download on a dvd or usb

When I went to Walmart to put all my pictures onto a DVD at one of their machines only a few would transfer? I connected directoy usin my USB cord.

My IPAD storage is maxed out!

Many are in albums. I do uses ICloud storage and I also have all backed up in google photos!

How do I access all photos, to transfer to other storage media, so I can know I have safely saved my precious 700+ pictures. Before I dump out my IPAD of pics!

Thank you,

Karenfromwingo