Could we get some information on the overhead that the headers add to unity?

[wes-kay]

I am looking at the current asset / disk size in the editor in the "Sprite importer" and it says the webp imported asset is larger than my png files. Since I don't trust that is there any info on what to expect the size to be in our build?

[netpyoung]

webp's size is size what you want. Imported size will be expended for preview.

webp importer's role is just for preview. So what you need is writing logic for how to use webp not for preview