The server load is the current overall load of the server caused by everyone, not just your site. Anything over 1 means that the server is behind on the processes. There is nothing you will need to do on your end, this is just a display reference to let you know if the server load is high or not. Even if it shows high, it doesn't mean there is something wrong with the server. A lot of servers will run on the high side due to the number of users and applications running.
If the server load is high and your site is having odd issues like photos no loading, or is extremely slow then you may want to contact your hosting provider so they can look into why the server load is up.