pub fn image_kind(bytes: &[u8]) -> Option<&'static str>Expand description
Which supported format signature these bytes carry.
Sniffed, never taken from the address. A download that went wrong — a
redirect to a login page or an error document — arrives
as bytes like any other, and writing those into a music folder under the
name cover.jpg is silent corruption that only surfaces months later when
something tries to display it. An extension read off a URL would not catch
any of it.
This checks the signature only. write_image also decodes the image and
checks its complete container before publishing any bytes.
None means: do not write this.