You will need to give Clustify permission to use the photos from your iPhone in order for Clustify to use the photos from your Camera Roll or Photo albums.

You can grant permission to use photos by changing your iPhone’s Privacy Settings:

• Go to iPhone Settings > Privacy
• Tap Photos
• Ensure Clustify is set to “On”

If Clustify is greyed out or does not appear in Privacy settings then you should check iPhone Settings > General > Restrictions.

Open Clustify, and you should now be able to use your existing iPhone Photos with Clustify.