I have a very large Wordpress image bank (over 600 images, all in use...!) and a new development will mean that i would like to change some of the thumbnail settings.
I have at the moment
set_post_thumbnail_size( 75, 75, true );
In the functions, which of course means that the thumbnail is cropped to fit. I would like to change this so that the thumbnail is scaled, rather than cropped
set_post_thumbnail_size( 75, 75);
But will this change the current images i have? If not, is there a way of doing this?