Understanding the use of assetId in Sanity.io

what is

assetId

used for? i thought in the beginning that i need it to reference my images, but for this

_id

is needed...

The

_id

of an asset is the

assetId

preceded by

image-

(or

file-

) and followed by the dimensions and file extension of the uploaded asset. I believe it may be used by certain libraries, such as

@sanity/asset-utils

.