Image editors to convert images to WebP for Ubuntu?

Is there a good image editor application for Ubuntu with which I can convert jpg/png images into WebP format? ImageMagick was a crap for me! With it, output webp image's size just increased!!!

There is a plugin for the Gimp that provides the ability to load and export WebP images. You can install the package (gimp-webp) from this PPA:

ppa:george-edison55/webp (Click here for instructions on using PPAs.)

The commands for doing this would be:

sudo add-apt-repository ppa:george-edison55/webp
sudo apt-get update
sudo apt-get install gimp-webp

Once the package is installed, open up the Gimp and you will now be able to export images to the WebP format:

The package is currently available for Trusty, Utopic, Vivid, and Wily.

_{Disclaimer: I am the author of the plugin.}

There is a webp package in Software Center by which you can convert GIF to WebP via commandline.

Also there's a paint for KDE, KolourPaint, which can save images as WebP.

16.04 Fixed

Since 16.04 imagemagick (or convert) does support webp, although it delegates to webp, so you need to install webp.

sudo apt-get install webp

But importantly things like convert img.png img.webp do work now.

Before 16.04 convert simply gave a png or jpg as output. The result wasn't a webp format. (You probably got bigger filesizes because it converted jpg with default (higher) quality)

Thumbnails:

display 'vid:*.webp'