Chunk_of_surprises
In this challenge, we are given a png image. But when we try to open it, we get an error. So we look at the hexadecimal inside the image and we see that the headers and the trailer are not correct.
As we can see on this website, the png header should be 89 50 4E 47 0D 0A 1A 0A but is 01 50 4E 47 0D 0A 1A 0A so the first bit is not good.
The second header should be IHDR but there is no IHDR so we add it by replacing the wrong hex value. We also modify the tailor as for the PNG header. 
And we got the flag written in black at the top.
