Making stickers out of photo’s

Hi all, for some or other reason when I highlighted the piece of image I want to use as a sticker and paste it in whatsapp(how all the tutorials show it) it still sends the whole image and not as a sticker ( all my friends iPhone's send the sticker if they do it in that way) Even when I drag the highlighted part of the image to whatsapp it still send the photo and not as a sticker. Please help its irritating me and can’t find help anywhere else. Am I missing a setting ? (I am on the newest software update) T.I.A