I have an image which I wanted to set the background as transparent for, which was pretty straightforward in Pinta due to a great tutorial. But I was left with a faint whiteish grayish outline when I pasted the image over a dark background.
The advice I found online for this was to increase the "tolerance" of the bucket fill param, but this didn't work for me. Adjusting the tolerance bit-by-bit, I found tolerance of 35 still didn't get rid of the border, and tolerance 36 applied fill-transparent to parts of my actual image.
So now I'm zoomed in to 1200% and filling-transparent pixel by pixel around my image. All these pixels are shades of gray, and I just leave alone everything that's black (which delineates the outline of my image). But there's got to be a better way to "fill everything in this region lighter than black" right?