Webp images are much smaller than png images. It would be really great if there was a plugin to convert all png images in vault to webp and update all the file links.
The interface should include the quality of the images. I think the default should be 100%.
This package might work: https://www.npmjs.com/package/webp-converter
Even better would be a toggleable option to automatically convert images to webp when you paste them into a file.
I do exactly that with this freeware
Once the images have been converted from .png to .webp, I change back their extension to .png and overwrite the original .pngs in the Obsidian folder. In this way I’m not forced to edit anything inside Obsidian
Doesn’t that break all links by default though 
?
I’m trying to find the right setup for this as well, but if I change the extension of my files from the filesystem (I am batch converting my files into webp from a script) my notes lose all their references to the images (which seems normal).
I haven’t yet found a good way to do this, do you have any advice?
[edit] Just realized that you’re renaming the images to .png, I misread the initial post 
I’m doing that as well, it’s the only way I found to automate this at this stage. I want to do better because I don’t like using a wrong extension but until I find how to do this better, it’s how it is 
The problem is that when you copy and paste images, Obsidian saves them as .png files.
I should check in the options if it can save them with another extension but, if I well remember .webp is not included among them
When I have to change .webp files to .png (I repeat: I only change the extension in the name, I don’t really convert the files) I do it with a mass renaming tool.
So the thing is neither long in time nor difficult to do