Hazards of increasing network size by changing the netmask

The ping won't work because the reply cannot be routed, as the router won't know where to find you 192.168.1.* machines. You'll have to change the subnet mask on all hosts in the subnet.

That said, why bother with those tiny bitmask changes -- if you have a large subnet, just make it /16 and be done with it -- what benefits do you expect otherwise?

By setting the subnet mask to /23 instead of /24 you would in theory get 255 more IP-addresses. However, this would require you to change the subnet mask on all devices already in the network. It would also increase the number of packets sent to the common broadcast address (192.168.1.255)

Another solution, which we use for our customers, is to add a new subnet - 192.168.1.0/24 - to the new computers, and add this to the routing table of your router. This would, if it is configured correctly, allow traffic from the 192.168.0.0/24 subnet to be sent to the 192.168.1.0/24 subnet and the other way around.