I would like to know once and for all, how to post an image that is not a thumbnail.

you see i posted an image from my first nude shoot today, and i dont have photo shop, but i do have a new iphone 4s and another old 6mp digital pentax dslr.

yeah i know, but any way, i found a free site that allows you to resize images etc but i cant remember what size i need, and so after an hour or so of faff i ended up just posting a small image lest i go insane.

so with said equipment and a mac, how does one post an image that is not a thumbnail.

thanks kindly

andrew