Additionally, there may be an argument for locality here. If every time you're serving an image, you need to look up a bunch of metadata for it, you can benefit

Additionally, there may be an argument for locality here. If every time you're serving an image, you need to look up a bunch of metadata for it, you can benefit from storing it in the same place. Then it's a matter of whether you rather encode the metadata in the image and store it as a file, or encode the image in the metadata and store it as a database entry. Now if you throw in having to do a little bit of post-processing based on various conditions, then the scales start to tip.