I like Imgur, I realise that if it goes offline, that is a problem but in the 10 years that I have been using it. Not really THAT big a problem if at all. Am I in that much a hurry to post a reply on the forum? Am I that desperate? I don't think so, I can wait until it comes back on.
The good thing about IMGUR is that it stores the photos chronologically of when it is uploaded, I can go back page by page easily. I can also use the same image link across multiple forums and platforms and link to it. I don't need to upload the same image on here if ocuk host images, then upload it again somewhere else. 1 upload, 1 link.
Free, cloud based storage, easy to use, works everywhere, even has an app.