Hey, its been a long time.

[Z-Man]

Yeah, that was just my silly way of saying "spotted the pattern"

[Jonathan]

I suspected that. You know more about these things than many people on this forum combined (by merging at least).

[Z-Man]

Nah, I just wait for you to give those hints that give it all away. On a side note, I did not get your overall brightness change hint, because I see no overall brightness change.

[Jonathan]

Still, nobody else claimed (s)he knows all I did yet.

Maybe the brightness change is not very apparent, but it's definitely there. Try blurring or downsampling. The result will be rather dark afterwards because this is rarely done with gamma correction. After brightening (automatic levels should do a good job) the difference will be clearer than ever.

[Z-Man]

Oh. Heh. Turns out I miscounted, and fell for the curse of small numbers, and my original theory was completely wrong. My new theory works better and even explains the brightness drop(s)

[Jonathan]

Oops. Interesting how a bunch of small dots can hide an image that really isn't that hard to see.

Anyone else who thinks (s)he knows what I did? It's truly given away now. I will post the answer by the end of the month if nobody objects, and if it isn't already posted.

[Z-Man]

It's truly given away now.

As long as you don't listen to my "start at 0" remark, because it was the wrong way round the way I meant it

[Fonkay]

I'm now horribly curious of the answer. Everytime I look at it I see something different. Now I see letters, only I'm not sure if they're really letters, so I'm not sure what to think.

[runemaste644]

Sometimes it looks like it moves

[Carnage]

When you said that the dots are covering the image, did u mean taking away the(some) dots would show the picture? O, by any chance, do the small black circles mean anything or coincidental?

Nice hijack, by the way.

[wrtlprnft]

I found out that if you scale jonathan's avatar to 16×16 pixels in kolourpaint 1.4.9 (without interpolation) you get something that looks like a smiley:
Coincidence?!

[Lackadaisical]

Since the small picture is just the upperleft part of the bigger picture (only mirrored diagonal, maybe it's a clue?), and since I assumed that both pictures had exactly the right amount of prime numbers, I expected that counting every white pixel in any n*n square in the topleft corner would yield the right amount of prime numbers up to n^2. This is not the case though (see the 6*6 square), so I'm stuck there. The 8*8 square did have the right amount of white squares though (maybe any power of 2?). Anyway, I'm rather anxious to see what the anwser is. (Do you study math or something Jonathan?)

[Jonathan]

Carnage: The dots don't really cover anything, but they reduce sensitivity of the human eye to certain patterns.

If you see black circles that means about as much as hearing satanic messages in songs when playing them backwards. They probably have to do with the patterns prime numbers tend to form though.

wrtlprnft: Hard to believe it gives that result. It would be pure coincidence, really!

With downsampling I meant downsampling with a proper filter, which is similar to blurring. Only the smaller size might help the human eye a bit. It might also not.

Lackadaisical: You spotted some patterns.

No formal math study at the moment.

Should I delay posting the answer?

[Carnage]

No, I find it too curiosingnessly.

[Jonathan]

You can continue guessing if you didn't look.