Is this a regular desktop machine or a laptop? If it's a desktop machine, and you know your way around one of them, I'd suggest:
1) Remove the Windows drive entirely and install a new drive. Maybe you have a spare drive around somewhere. If the machine is old enough, you'd need an IDE drive rather than a SATA. Use the same connector as before so the boot order will remain the same.
2) Replace the Windows drive temporarily and cable it to a different connector on the motherboard.
3) Boot the machine and check the BIOS to make sure it sees both drives, and that the new drive will be the boot device.
4) Disconnect the Windows drive.
5) Install Ubuntu on the new drive.
6) After you've rebooted and checked everything out, reconnect the Windows drive and reboot.
7) You should be offered the ability to mount the Windows drive into the Linux filesystem, probably under /media. If you do that, you'll be able to access the entire disk. Copy the photos off. If you're ready to get rid of Windows entirely, have Linux format the Windows disk to its native ext4 format. Now you'll have both the new disk and the old disk for storage. Read this document to learn how to tell Linux to mount the old Windows drive automatically at boot.
Do they watch Netflix? If so, you'll need to install pipelight. Works with Amazon Instant, too. Services like Hulu just use Flash. Here's a quick overview for installing pipelight.
If you know how to use cron, you can tell it to automatically back up the pictures and anything else important from the Ubuntu drive to the newly-reformatted backup drive. Then there will be another copy just in case. Something like this in /etc/crontab
That runs rsync at 4 am every day to backup the Pictures directory to the backup location.
0 4 * * * root rsync -a /home/family/Pictures/ /media/windows/backup/
If they turn the machine off at night, read the section in the cron documentation about anacron or use the at to run backups.