SEO. What is the length of the image (file) name should be?

Question

Google

Good afternoon!
Optimizing a photographer's website. Lots of images, all have alts, compressed just right. But here are the names of the files themselves. I gave preference to Latin letters separated by "underscore" and asked myself: "What is the preferred length of the file name for search engine optimization (seo)?"
Thank you!

Answer 1

I don't care what

Answer 2

There is an opinion that Google does not like too long NCs, considering them to be spam. And if the url of the image page is formed from its long title, then maybe this is not good.
Yandex, it seems, is not noticed in this.

Answer 3

The length of the name must be valid for the file system.
For most FS , this value is 255.

Answer 4

I do no more than 80 sbp