inadvertent whatsapp messages

Hello,

There were two instances recently when my whatsapp sent images to people seemingly all by itself, without my involvement. In one case the phone was in the pocket and the image sent was a photo of jeans pocket taken from inside, apparently right before the message was sent. The image was sent to two contacts at the same time. In another instance, an image I had intentionally sent earlier to contact A was all of a sudden, unintentionally, sent to contacts B and C, again to two contacts at the same time.

I am probably touching on the screen and the phone thinks I am clicking on buttons.

What can I do to eliminate this possibility?

The first case happened with Android 7, the second - after an upgrade to Android 8. The phone is Xiaomi Mi 6 if it's important.

Many thanks,

leonid