You will need to install a user script manager extension to install this script.
When you visit IMDb gallery pages, this script automatically expands all of the images so you don't have to click on each one to view the larger size. If you mouse over an image, you will see a zoom icon in the top-left corner that links to the FULL size image, which is often much larger than what is shown on the image page.
(Tested in Firefox with Tampermonkey. Please give me feedback if you have any issues!)
Fix for new media-amazon.com urls
Fix to work with imdb's new SSL image server