Hey George,

Whatsapp has introduced this as their latest feature to auto-delete images of any formats, videos, GIFs.

This feature has been included to improvise its user experience and to avoid unecessary memory increase and security reasona as well.

When you attach an image in a chat at the bottom beside add captions field, you might see an icon as 1 clicking on it will enable your video/image to be viewed only once by the receiver.