The demand for using BTC for it's real use case, which is to move and store money, will be an S curve, and when it happens, you don't want the blockchain cluttered with jpeg spam.
The demand for
bitcoinblockspace is expressed exclusively through the fees paid per byte. If jpeg encoding transactions pay more fees, then
they WILL clutter the blockchain, since profit driven miners will include them
and they will clutter the blockchain. You can only slow them down slightly by making them jump through hoops like sending them directly to willing miners.