What is Alpha Channel?
In graphics, each pixel has transparent information. Normally in a 32-bit image, there are 8-bits for each of the 3 colors Red, Green and Blue and one extra channel for either converting or ignoring. This extra channel is called an alpha channel, this is actually a mask, which specifies how the pixel colors should be merged with another pixel when the two are one above the other. Technically it controls the transparency and opacity of a color. If the color is at 255 for the channel red the alpha channel is opaque that is the darkest red. And if the value is 0 then the image will be transparent. Alpha channel can work for both background and foreground.