Find Randomart of existing ssh key
Solution 1:
try this:
ssh-keygen -lv -f .ssh/id_rsa
This can be found in ssh-keygen's manpage. As for randomart's purpose:
"The randomart is meant to be an easier way for humans to validate keys.
Validation is normally done by a comparison of meaningless strings (i.e. the hexadecimal representation of the key fingerprint), which humans are pretty slow and inaccurate at comparing. Randomart replaces this with structured images that are faster and easier to compare."
This text was taken from here: https://superuser.com/questions/22535/what-is-randomart-produced-by-ssh-keygen