Codeforces' Hidden Feature — Multiple Profile Images!

Revision en13, by HYPERHYPERHYPERCUBELOVER, 2016-02-14 23:13:23

I have noticed a strange feature while conducting some experiments. Look at the following. My large profile picture and small profile picture look different.

I can't believe that.

You can see that my profile pictures look different here and here. Still not convinced? Upload this and check how your profile pictures are changed.

Why does this happen?

I uploaded this to change my profile picture. The result was interesting. The large profile picture was almost black, but the small was white. I thought that Codeforces uses Nearest-neighbor interpolation to scale pictures in proper sizes. (This is just a guess!)

Nearest-neighbor interpolation selects the value of nearest point and does not consider the values of neighboring points at all. I tracked which values are used and found how to make profile pictures look different.

So, how did you do it?

I used this python script to create a 3600x3600 image that will make your profile pictures look different. Requirements are Python 3 and PIL. First, save a 300x300 image that you would like you use as the large profile picture as pic1.png. Likewise, save a 80x80 image for the sub profile picture as pic2.png. Finally, run the script and upload pic.png. pic1.png will be the large profile picture, while pic2.png being the small profile picture.

I hope you love this feature :D

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en13 English HYPERHYPERHYPERCUBELOVER 2016-02-14 23:13:23 0 (published)
en12 English HYPERHYPERHYPERCUBELOVER 2016-02-14 23:12:55 5 Tiny change: 's is just guessing!)\n\nNear' -> 's is just a guess!)\n\nNear' (saved to drafts)
en11 English HYPERHYPERHYPERCUBELOVER 2016-02-14 21:12:40 0 (published)
en10 English HYPERHYPERHYPERCUBELOVER 2016-02-14 21:09:34 0 Tiny change: 'per sizes.\n\nNeares' -> 'per sizes. (This is just guessing!)\n\nNeares'
en9 English HYPERHYPERHYPERCUBELOVER 2016-02-14 21:06:46 25 Tiny change: 'per sizes.\n\nNeares' -> 'per sizes. (This is just guessing!)\n\nNeares'
en8 English HYPERHYPERHYPERCUBELOVER 2016-02-14 21:00:47 30 Tiny change: 'ile image are different' -> 'ile image looks different'
en7 English HYPERHYPERHYPERCUBELOVER 2016-02-14 20:57:37 205 Tiny change: 'ile image are different' -> 'ile image looks different'
en6 English HYPERHYPERHYPERCUBELOVER 2016-02-14 20:51:28 8 Tiny change: 'ile image are different' -> 'ile image looks different'
en5 English HYPERHYPERHYPERCUBELOVER 2016-02-14 20:50:41 819
en4 English HYPERHYPERHYPERCUBELOVER 2016-02-14 20:04:33 256
en3 English HYPERHYPERHYPERCUBELOVER 2016-02-14 19:43:36 722
en2 English HYPERHYPERHYPERCUBELOVER 2016-02-14 19:23:50 50 Tiny change: 'different!\n\nYou can't ' -
en1 English HYPERHYPERHYPERCUBELOVER 2016-02-14 18:53:55 486 Initial revision (saved to drafts)