Hello. I'm implementing qt image plugin for Half-Life sprites (source code on bitbucket)
As far as I understood KDE requires .desktop service and mime-type for the new type of images to be installed. I made both. Now gwenview and kolourpaint4 can open and view images of the added format, but other applications like dolphin or krusader still don't show previews. Did I miss something?

I'm using KDE 4.14.2 and Dolphin 4.14.1 on Debian jessie i386.
For testing purposes you can download this sprite

Found out, it also needs another .desktop file (ThumbCreator service) to show previews in dolphin and other apps.