Image is picky about specific formats

[captncraig]

I tried running trayhost with an arbitrary png I found online. It panicked because it decoded to image.Palletted rather than image.NRGBA.

Perhaps the invert routine could be relaxed to work more generally.

Or maybe https://godoc.org/github.com/disintegration/imaging would be a good alternative. They have a simple invert function that works on any image.

[dmitshur]

Relevant code is here.

Hmm. Yeah, it's definitely limited right now.

Generally, I prefer to pull in as few dependencies as possible. But that one looks quite reasonable.

Let me think about this for a bit...