be careful. I don't know much about icloud nor how you configured iCloud. Are you paying for iCloud storage? do you do a complete backup to iCloud?
Why I ask. iCloud is photo sharing is a syncing facility. It is meant for sharing your photo across multiple devices. You delete a photo on one device and you delete them on all devices. You need to connect your iPad to a computer and move the photos to your computer.
This is controversial around these parts, but I recommend you get
your photos out of the Apple ecosystem and store them as one photo
per file on multiple external storage devices.
For long term storage, don't rely on usb memory sticks nor
external ssd drives. LoC does not have data on the
reliability of usb memory sticks. Apple seems to be saying
do not store photos on external ssd drives. One device
should be off site. Using a cloud service is fine.
Remember a lot of cloud services are sync services. That is
should the file be deleted on the local device, the photo will be
deleted in the cloud. For this reason, I never install
the cloud service software on my computer. I use only file
upload. For those who complain, my assessment is that the
apple Eco-system doesn't match Library of Congress's requirements
for digital archiving.
informative video:
http://www.digitalpreservation.gov/multimedia/videos/personalarchiving-photos.html
printed version
http://www.digitalpreservation.gov/personalarchiving/photos.html
General information on digital preservation:
http://www.digitalpreservation.gov/personalarchiving/
R