add image upload with dither at ATC_GICISKY_Paper_Image_Upload.html

[zba]

Hi,

I added dithered image upload to your code, may be you interested to adopt. you can try it on my github page https://zba.github.io/atc1441.github.io/ATC_GICISKY_Paper_Image_Upload.html result like this:

also please note this change: line 251

On my screen (I not sure what is name but it 296x128 1.9") , without checking other channels RED mask was created wrong and red and black collors was swiped, it easy to make it optional, but I not sure if need.