Copy pasted from the other thread. Stop freaking out guys.
Fucking retards. A .png file is made up of a header and a series of data chunks, starting with an IHDR chunk and a IEND chunk. The header is always a series of 8 bytes: 89 50 4E 47 0D 0A 1A 0A
In the image you can clearly see this is a normally formatted png file. This will never be opened by any browser as anything other than an image. It may be possible to hide executable data in the chunks portion of the file, but you would need a specialized program to extract and run it. A browser or image viewer would never run it.
In addition, why the large file size? Look to the right of my image. There's a bit depth of 24, meaning there are 24 bits of information per pixel, or 3 bytes. A megabyte is 1,000,000 bytes and the file is 640 x 960 pixels, so let's do some math. ((640*960) * 3) / 1,000,000 = about 1.8 MB, which means the image was compressed. There is no room in the file to hide an .exe anyways.