If you're short of bandwidth or limited by a quota, uBlock Origin can be toggled easily between allowing or blocking all images. It's what I use to make my 750MiB per month GSM/4G connection last.
[1] https://github.com/gorhill/uBlock/wiki/Per-site-switches#no-...
Edit to Add: TBF, most users may not have the technical know-how to use it in this way.