The same picture is used in Safari on OS X. 
Only complaint I have is the white edges that appear.
Fixed
I added an empty row of pixels at the top (making it 500x500 instead of 500x499). Made the entire first column −80% brightness and +30% contrast. Then all but the most dark in first column plus 1px down −20% brightness. I then adjusted that 1px back +5% brightness or something, lost track of some slight extra changes unfortunately. If someone cares that specifically. 
500x500 (34 KB)

Would be delighted if you replaced it with this one. 
Scaling it to 250x250 only saves 6 KB, and the issue resurfaces on the top when I scale it to 152x152. Can probably fix it if desired. The current one is 15 KB. Never mind, looking at the other data this is insignificant.