[ghshephard]

10.0.0.255, 10.255.255.1, etc.. are valid ipv4 addresses. The only restriction in IPv4 is around not setting all of your host bits to 0 or 1. There are no restrictions regarding the number "255".

If I have to quibble with infographics like these, is that they obscure the fact that IPv4 was able to have variable length subnet masks, I.E. You could have networks that were 24 bits in length (/24) or 27 bits in length (/27) - depending on your requirements. With IPv6 you don't have that freedom - every network is a /64, so, if you are only going to use two hosts on your network (for a network link) - you are still assigning 2^64 addresses to that link, of which you will only use 2, resulting in a "wasted" 2^64 - 2 hosts.

It's odd the first time you do it, but eventually you just learn to live with the fact you have, for all practical purposes, unlimited address space in IPv6 - so wasting 2^32 times as many IP addresses than you had in ALL of IPv4 on just a single routed link turns out to be no big deal.