Very stylish. I really like the random preview options. And the presets. I'd love to use this for a game or other bit of art!
The only trouble I had was accidentally using the dither "import" button when I meant to use the preview "import" button (and was alarmed by the now massively-resized left panel). Since they're both simply labeled "import" (and the possibility of importing the threshold map(?) may not be immediately obvious) it seems like maybe this could be an easy mistake to make? Possible solutions: move the import buttons next to their respective save buttons (like a get/set or download/upload pair); tweak the labels ("import threshold map" & "import preview image"); add a "threshold map options" title to match the "preview options" title.
A tiny feature wish-list:
- hotkeys for bumping the current layer up/down (rather than using the mouse)
- resizable panes (mostly so I can view the preview larger and hide the threshold map)
I've already spent awhile just playing with the options, saving previews. Nice work!