psychedericThank you for think great plugin ( and i think wordpress need it ).
I have some suggestions :
1. In an "open" "multiple author blog", i think we need to rezise images, this is really necessary, and as i so you just redefine the image size in html, but you don't 'resize' the image really.
2. So there is a need of a little option to define the defaut image size, and/or the maximum image size (then we recompress the image with GD ...)
You know A simpler solution could be just to test the image size, and oblige the author to send and image at the right size (i think you can find something in ajax like that somewhere)
The last suggestions : I think the widget really need an option to choose where (in which pages) the plugin is displayed ( for instance : is_single() ...)
One more time thank you for your work;
