photo detail... Is this possible

[justal]

Is it possible (or is there a hack / plugin that will allow me to do it)... I want to have images displayed as usual.. i.e. a thumbnail, then the intermediate size image but want to disable the full size image and instead just show part of the image at full size within the 'intermediate' sized image window.

I hope that makes sense. Basically rather than allowing people to access the full size, high resolution images I want them to have access to just a portion of the image at that resolution.

Any suggestions??

Alan.