Hi Ozziesmom,
Thank you for posting in the Apple Support Communities. It sounds like you'd like to upload photos to your iPad that are stored on an external drive, correct? If so, we would love to help! You mentioned that you're using a Lightning to USB 3 adapter, which may have other power requirements to work.
Specifically "Note: The Lightning to USB 3 Camera Adapter can be powered with a USB power adapter. This allows you to connect USB devices with higher power requirements, such as external hard drives, to iPad." which can be found in:
Connect external devices or servers with Files on iPad
Please let us know if you have any additional questions. We're always happy to help.
Cheers!