For years and years, when I look for new icons for objectdock, i'll find great .png files that just aren't recognized by ojbectdock. In other words, I put the .png file in the appropriate stardock folder, but when I go to change the icon for an objectdock shortcut, the .png file doesn't show up in that folder.
And to make matters worse, I can physically drag that .png file into objectdock and it will work like all the other icons. So the objectdock software clearly "understands" the file. But I am simply unable to select it for any working shortcut.