I figured you could create subfolders inside the images folder.
Example:
Image URL: domain.com/Rtz.jpg
Path: public/i/R/t/z/Rtz.jpg
This would prevent everything from being in one directory.
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So I could configure nginx to receive these requests in a php file that would be responsible for creating the image in the browser, but that would be very heavy. Php is responsible for everything.