1. I think we can both agree that text can be used to redirect people to onion links (like a dark web wiki), I even think that text alone should be enough. All things apart, I found on the net that it is possible to store data (images) as text (binary) then recompile them again using specific tools.

2. It is actually safer to do it on an immutable chain than going for an onion option, immutability will allow fire-and-forget approach, which is far safer than using tor which will compromise your browser fingerprinting uniqueness.

3. Well, the problem here is that the front-end won't be necessary, people will just need to use a block explorer.

4. What do you think about letting the user choose? like giving people the choice before posting something to check a mark if they want the post to be immutable or not. This could be attractive to both those who want immutability and those who don't want nor need it or even cannot work by it due to regulations or commercial contracts.

This is all theorizing of course, but the steem blockchain needs to evolve, to adapt according to people's needs while keeping its core value at the same time. The immutability thing is overrated, we have already seen with HF9 what would happen if someone powerfull wants to play god.

You can read the post and comments here for more information:

https://steemit.com/stopthepowerdown/@lukestokes/is-steem-centrally-controlled