To solve this problem you can use a WhatsApp feature where you can see the pics in group only.. without saving them to your phone.
Please follow below steps:
1) Click on 3 dots shown on the right top corner in the group.
2) Click on the first option i.e. GROUP INFO
3) Three options shown below the group name i.e. mute notifications, custom notification, Media visibility
4) Click on the third option MEDIA VISIBILITY
5)Click on "No" option
Now the media will not be saved in your phone. but it will display only in your group chats.
Now that you know....act and inform your other group members in other groups.
This feature is only available in Group, not in individuals.
Am sure some people will need this.