What is the correct way to delete images on the server and give the images to the user?

Question

Images

Suppose the image storage is implemented in the form:
imgs/a/b/c/abcsef.jpg
imgs/c/b/d/cbdfgh.gif
and so on.
1) The path to the image is stored in the database. There is a special field, when set to 1 (true), the image is considered deleted. As far as I know, immediately deleting an image is bad for the file system + load on the server. How to delete images correctly (massively - accumulating a certain amount)? Then, what then, because there will be a strong fragmentation.
2) What is better, to form an image on the fly? Or store, for example, a reduced copy of the file?

Answer 1

1. Remove immediately.
2. Cache all the necessary image formats.