What I use for image hosting is
Servimg.com - Free image hosting service And I am more than happy with the conditions of use and the service itself. I'm using it for years now and I haven't change my mind yet, so they are very nice. I don't think you can host your image without a (free) registration, but it is worth a 20 second or so registration. Unlimited, you see ads only on the website, not on your image or a place(website) where you show your picture. You can link to show your picture directly, which means it is not linked of anything, its just a pure picture. And for years now none of my pictures got deleted. So I recommend it.
Other very nice service is provided by
Free File Hosting Made Simple - MediaFire for file and image hosting, great thing is when you make an account there you have your own folders where you upload your stuff, so you can keep larger number of files. You can upload files and photos even if you are not registered just the same, but you don't get to organize folders that way. It's free, but there is a PRO edition if you really need it. It's a great service, I am using it for years now, it's recommended by worldwide computer magazines as well. You can give it a try. I haven't decide to move away from it yet.