Dev Notes: Modding on Linux - openly-retro/stellaris-machine-robot-expansion GitHub Wiki

My advice:

• Use GIMP for creating DDS files, and save things in XCF whenever possible
• If you are switching over from Windows or dual-boxing, go get the XCF plugin for Paint.net and export everything to XCF. https://forums.getpaint.net/topic/23650-gimp-native-format-filetype-plugin-xcf-xcfgz-xcfbz2/
• Use INKSCAPE for logos, icons

How to get DDS previews:

https://askubuntu.com/questions/617047/how-to-preview-dds-and-webp-images-on-nautilus