Media content such as pictures, videos etc. are typically not stored directly on a blockchain. The reason behind this is that these take up huge amount of space, so the blockchain would grow insanely large very fast. Just imagine if someone uploaded a 5MB picture to the Bitcoin blockchain: now everyone would have to download these 5MB of data before getting the latest transaction data. Now do this times 10,000 pictures, and you will quickly realize how problematic it would be.
It is a bit more possible with a PoS blockchain like Steem, where only a certain amount of people actually downloads the entire blockchain. It would be very easy to clog it up still though, if people upload photos/videos more quickly than the block producers can download them.
In other words, blockchains are not really good for storing content that requires a lot of data. I hope we will find a solution to keeping data such as pictures and videos on a blockchain in the future, but that would probably take a lot of innovation still.
As of right now, when you upload a photo to Steemit.com or busy.org (or any other app), this gets hosted on a regular web server. I think Steemit and Busy.org are using Amazon Cloud Servers, but I'm not 100 % sure. So these apps will have the ability to delete your photos from their server if they wish. So right now there's no difference in uploading a photo to Steepshot compared to Instagram, it's only that a link to the photo is permanently stored on the Steem blockchain in the case of Steepshot.
Thank you for explaining this. Really appreciated!