What does it mean when snapchat disk is full?

When I try to send a snapchat it sends a popup message that says Disk Full. Please free up space on your disk and try again. I don't know what disk this is referring too… I have an iPhone and I've tries clearing all the snaps I've been sent but that's it. Any ideas?

How much free space is on your phone?

The disk it is referring to is the Hard Disk, also known as the Hard Drive or Memory. You should try removing sent images too and maybe deleting un-needed music, videos and apps if you really want to use snapchat. :)