Sorry but, do you have at least an idea of what is an SSH keypair / keyset, a PKI, how and what those are used for and most of all, what is a key randomart? a hint, you won't be able to rebuild a key by just extracting random patters from images
Randomart is nothing but a 'quick way' to integrity check and match the PUBLIC keys ex with an host when you ssh somewhere, like hash visualization, is generated on top of the fingerprint
If you wanna still dig deeper on how this works and figure out some reverse engineering logics, i'd suggest you this reading, quite old but still solid
Sorry but, do you have at least an idea of what is an SSH keypair / keyset, a PKI, how and what those are used for and most of all, what is a key randomart? a hint, you won't be able to rebuild a key by just extracting random patters from images
Randomart is nothing but a 'quick way' to integrity check and match the PUBLIC keys ex with an host when you ssh somewhere, like hash visualization, is generated on top of the fingerprint
If you wanna still dig deeper on how this works and figure out some reverse engineering logics, i'd suggest you this reading, quite old but still solid
http://www.dirk-loss.de/sshvis/drunken_bishop.pdf