Depends how your website is designed but I would use php with glob() to find all the images on your website and use css to layout the images and php to create the links.
Basicaly some gallery software - I used to have a gallery setup like that but can not find my old code now.
All Right, If you want to see all of your website images only then it’s very simple just open Google and then type site:websiteurl and press enter and click on images and you will be seeing all the images of the website which website you will type after site: