I am really happy you like the plugin.
nick0 The ability to exclude some images from webp conversion might be nice (where the webp image has a larger file size)? - eg
I will look int this in future update, I will have some time next month.
nick0 Can webpconverter handle srcset images?
So far it handles
<source> nodes, which are usually included in
<picture>. The problem with
<img> is that it contains several image paths and I would have to parse those into separate image paths. This of course can be done, but I will have to change the logic how the plugin handles a HTML node. I will see how well it goes.
In the meantime you can use the snippet included with the plugin. Just feed it the image path and it will do the rest. So in this case you can do something like
[!webpBackground? &src='assets/images/...'] 480w,
I think that you can also replace the image path by phpThumb call in the second case, but please test that carefully.