RE: SteemIMG will be down for a major server migration... yes again.
Well it is an acceptable solution for steemit.com but yes valid point for anything else besides steemit as a way to view the blockchain.
Also you could say the same thing for any image hosting website that the uploader doesn't own personally. Placing images in a server that is not 100% in your control & owned by someone makes that image no longer a decentralized one. DirtyIMG doesn't even hold the image for more then 15 minutes making it more decentralized then any other in reality but also you can't access the image again so... lol. The blockchain isn't a good place to hold the image as well due to block size issues A post of mine about this. Getting truly decentralized images is quite hard to do , there are options including https://ipfs.pics/ but this still relies on it being stored somewhere on someones server at cost in at least one place and although this is shared between many computers it can still go down.
That is why I host my images on my own IPFS node. Unfortunately, I still have to rely on the central public IPFS gateway (ipfs.io) to make them available, as Steem is not integrated with IPFS yet (but it is in the roadmap). Ideally, media content would be linked by its IPFS path and retrieved using a site-specific gateway or a local node, so we would not need to rely on the single gateway server.