Stamp bug ? (little bug)

I made costume from a list (a pure black square 10 x 10 : (0,0,0,255))
i stamp it
The pentrails are different from the original list !
The entire right border is a little different...
pixels of pentrails:
pixel of original list

If i stamp the pure black square and then a pure white square on top (to erase it...)

a small border on the right is still there...

The problem seem to come from the stamp function...

Pretty sure this is because of dithering -- the deliberate fuzzing of sharp edges to prevent jaggies when the edge isn't exactly vertical or horizontal. Jens says it can't be turned off; it's Javascript doing you a favor.

Spookily I ran into a similar issue today


The sharp GALAXY MAP was generated using the write block and I turned the pentrails into a new costume but it is fuzzy compared to the original

How do you turn a list into a costume?

With this:
The list does not contain x y coordinates, it's just a list of RGB color and the transparency (opacity)
The number of records must have WIDTH X HEIGHT records, so a 10 X 12 costume have 120 records (rows)

Watch the example in SPRITE2 i made it for you...

I thought you meant a costume that looks like a list watcher!
I know how to use the 'new costume' block.