When you are running low on the number of colors supported , then moving from one color to other (gradient) will cause bands to appear (less steps in between).
Dithering reduces this by placing random noise in color steps. With dither, we can use a noise of available colors to give an illusion of unavailable colors:
RGB_565
has low precision (2 bytes) than ARGB_8888
(4 bytes). Due to low color range, RGB_565
bitmaps can show banding and low color range. Hence, dither flag is use to improve perceived image, and give an illusion of more colors.