  The current large blockchain systems (BTC Lightning network, Ethereum, etc.)
are generally facing the problems of low persistence rates and high storage
costs. Therefore, users tend to store single modal (textual) information on the
existing blockchain systems. Inspired by semantic communication algorithms,
this paper presents a new algorithm to solve the serious imbalance between
textual and visual modals on blockchains. After semantic sampling of the
original visual image, the resulting semantic text will be stored on the chain,
and the end users can reconstruct a semantically similar image using the
\textbf{R}elative \textbf{O}ptimal \textbf{S}emantic \textbf{I}sotope
\textbf{S}election algorithm. Experiments on the DIV2K dataset show that the
blockchain with our algorithm can achieve 430,000 times the storage capacity
and 550,000 times the persistence rate for the original visual data with
acceptable semantic information loss.
