To remove a picture from the LOOP simply go to Setting > and choose photos. You will find all the pictures that your contacts have sent to you. Choose the pictures you want to remove from the LOOP. When you select a picture to be removed or deleted there will appear a mark on the picture so you can see which pictures you have selected. In the bottom right corner there will appear a bin. Simple select the bin and your pictures will be removed from the LOOP.
When you remove the picture from the LOOP it doesn’t automatically delete the picture from your tablet. When you go to the picture storage on your tablet you will find the FamilyLOOPED album. There your pictures are being saved. So if, in the future, you want to add the picture you can.