In order to store picture, transfered as a base 64 encoded String in the message

I wanted to ask, what is the limit for column values (since the wiki is down just now)

the row has a limit of 2GB, it should be enough for pictures, but a single column Row, has also a limit of ~2GB?

Is it critical with replication? Is it better to cut down the String in shorter pieces and store them in different rows to support more easily read/write towards replication?