Wordsets are much more attractive if you add a picture - otherwise you're presented with a batch of ubiquitous Ws which blend into one another. To avoid copyright issues, websites such as flickr are good to download photos from. Flickr > Search (top RH side) > Advanced Search > scroll down to the bottom > check the boxes 'Only search within Creative Commons-licensed content' and 'Find content to use commercially' = bingo. In order to be doubly copyright safe, add a link to the photo on Flickr with the name of the photographer in the description of your wordset.
This may sound like a bore, but it really enhances the other users' experience of learning on memrise (in my opinion). And after you've done it a few times, it shouldn't take more than a couple of minutes to do this. Go oooon!