Just like why u can't sell a night shot of Eiffel tower - the lighting is patented and copyrighted. If the cloth designs are copyright or IP-ed, u're basically asking for trouble. If u want to sell pics to stock or microstock, u'll ve to send in model release form (assuming u've no problems with the cloth designers). Of course, if the models sign the forms, lucky u. Nonethelss, this procedure is even the same for national geographics. Yes, even landscape shots require property release form. For blog usage, u could say that u upload the pics for editorial purposes and u might want to check that one up.