Hi ting208!
It sounds like you’re unable to flag and add photos to reminders, and we're happy to help. If you haven’t already, please try restarting the iPad:
Restart your iPad
If the issue is still present, please back up your iPad before proceeding:
How to back up your iPhone, iPad, and iPod touch
Once you have backed up, you can reinstall the iOS software using these instructions:
If you can’t update or restore your iPhone, iPad, or iPod touch
If the issue is still present, try restoring the iPad to factory settings and setting it up as a new iPad:
Restore your iPhone, iPad, or iPod to factory settings
If this issue is present after restoring to factory settings, you should contact Apple Support using this link:
Contact Apple Support
Cheers!