I raise this issue about once a year in the hope that something might have changed. The courses I’ve created for my students are full of stupid mems. Sometimes they’re just pointless - maison/house will be accompanied by a picture of a house, for example - or they’re just random idiots posting their amusing pictures. It means that a useful mem gets lost among the verbiage. I tell my students not to bother with the mems, that it’s a part of Memrise that is effectively broken. There sometimes appears to be a delete option but it doesn’t seem to work. Please trust course creator’s enough to keep their courses in order.