@gambe945, I'm afraid none of these can be used as they don't have a transparent background. Plus, some of them have recent, good-quality cuts in the megapack already. Also, keep in mind that we have been accepting 250x250 cuts for quite a while now and some of these look to have been cut from sources for which this would have been possible. Before making any further cuts, have a look at this thread which has plenty of guidelines and practical tips on how to cut