For pixel-art or images based on measurements (e.g. spectrogram), it can be useful to use nearest-neighbor scaling instead of linear.
A proposal to add make it possible to change image scaling mode. One possible api:
img := paint.NewImageOp(img)
img.Filter(paint.FilterNearest)
img.Add(gtx.Ops)
Of course the API could be also implemented in other ways.
SGTM, except that I prefer a plain field:
img.Filter = paint.FilterNearest