#868 Experiment about webp and bpg

[Emmanuel Engelhart]

JPEG algorithm does not perform really good in comparison to new file formats like webp or bpg.

Re-encoding jpg pictures in one of this format would allow to reduce the global ZIM file size without loosing in picture quality.

The problem is that both of them are not well supported in browsers/web components, so we would have to propose a javascript decoder in the ZIM file itself, something which is more CPU intensive than using the standard core JPG decoder only.

[Emmanuel Engelhart]

Many scrapers support now Webp, MWoffliner included.