By increasing the smoothness radius, you can remove more pixels from the edges and make PNG clearer.
This option makes the pixels on the border between transparency and opacity semi-transparent. If you remove the color and the edges of the image still have a pixel or two of the old color, you can refine the edges and smooth them by enabling the 'Smooth Edges' checkbox. For example, if the color that you're removing is red, then it will also remove cherry-red, rose-red, wine-red, and similar shades of red. By default, 30% similar color tones are matched but you can change it as you see fit. To match similar color tones, enter the similarity percentage in the settings. This online browser program replaces any solid color and its close color tones in a Portable Network Graphics (PNG) photo or picture with transparent pixels.
