I'm not sure where the correct place is to post this but.
I have two slideshow galleries (non-floating lightbox + thumbnail controls) on my website and every time I try to change the Hero Image bounding box size the images remain the same size, ignoring the new dimensions the New Hero and New Thumbnail settings are set to scale to fill proportionately so as not to result in clipping, but that only affect newly-added images not existing ones.
The result is I have to manually scale each image to fit properly and it doesn't always retain the change (reverts back to before) which is not such an issue when you have 3 or so but when you have 72 or more then it becomes a headache. Add on needing effectively having two websites with one mobile version and this becomes long-winded.
(Above) Screenshot from Muse. The sheep image should fill the space in height between the blue guidelines. It's a bit hard to make out as the background is black. To avoid clipping, vertical letterboxing is expected.