No, that seems to be different.
If it were that you'd see a grid when you open the image.
This image is more like the image in the OP.
With this image there are two colors (black and less black) one of them is set to be transparent but 4chan keeps the original color when it makes the thumbnail resulting in the thumbnail being all black.
When the image is opened the image is properly displayed and there is transparency.
Rather than setting a color to be transparent, the image in the OP seems to have a color set to be another color and I have no idea how you'd accomplish that.
> seems to have a color set to be another color and I have no idea how you'd accomplish that.
pic related uses a color profile.