This was mainly to fix bugs, but I didn't want to release a new version without some new stuff in it.
So, from v0.4.2, you can use PNG images for workshop icons and truck/trailer skins. You don't need to convert them to DDS files, ETS2 studio does that for you. :)
Pretty neat, ha? :)
More image formats can/will be added. Let me know what you need/want, and I'll add it (if possible). :)