Another way to think about this is, for every 32 bit RGB pixel in an image, all the combinations of 16 million colors (or more as high dynamic range, if you forego the alpha channel and use the fourth octet for aditional color space; your choice) for even a 2x2 unit punnet square are quite insane to consider.Technically, with just four pixels, it's a set of combinations matching the entire IPv6 address space, since it's a full 128 bits of entropy.
A 2 pixel by 2 pixel image, at 32 bits per pixel, packs enough bits to max out all possible MD5 hashes.
[0] https://en.wikipedia.org/wiki/128-bit