Guest Posting… Image??

Hi – I have “uCan Post” plugin so that guests can write posts which i can then simply accept or deny… but I want the guests to be able to upload images to their posts… but for some reason you have to be a “member” to be able to upload an image from ur PC into ur post…. Please please can someone show me a way around this?? I find if users have to log into wordpress etc etc they will just get confused and it’ll ruin my site. Thanks…