I just found a way to host images via the simple planes website. This allows anyone to see them, as far as I know. I have actually been doing this for quite a while now, in my bio, (with my pictures of the posts other people made of TheMouse) but have not realized how useful this was until just a second ago, when i was thinking about how I could get it so Monarchii and other indonesians can see images, now that imgbb is blocked for them too. I wanted to show Monarchii this picture:

This was hosted by the simple planes website, so everyone that is able to access the website should be able to see this. How did I do this? Quite simple, and yet not simple at all. Let me show you.

First, choose the screenshot you want to use. Make sure it is downloaded in your photos. Then, open simple planes. Create a new build. (Make sure to save your own build first)
Take the screenshot you want to use, and add the screenshot you want to host, and upload it as a blueprint. (These steps are essentially what you would do to make a custom thumbnail.)
Click the share aircraft button, and zoom in on the blueprint. Take the first screenshot so it perfectly fits inside the screen. (avoid black edges)
Upload the plane as an unlisted post.
Go into your recent unlisted posts, and go into the post you uploaded.
Now, right click on the crafts thumbnail. It will look like this:

Click copy image address, (for me it was copy image link, but its the same thing)
Then, in your forum, (or plane description) do this:
![] (paste image link here)
Without a space in between. For me, the image link was this: https://jundroo.blob.core.windows.net/simpleplanes/GameData/aircraft/1384/9152Fj-UserView-0.png

My image that I wanted to upload looks like this:

Success! It worked!
(this is the post I used to upload the image at the top, and right here)

Summing up:

So, it works. It is possible to host an image with the simple planes site. Everybody should be able to see it, and it will not be blocked. This is not perfect, however. There are many problems with it. (and many great things about it)
Pros:
-Everyone can see it. (It is not blocked.)
-Does not need anything off site. It is all contained within the site. (and the game)
-It is a cool way to do things.
Cons:
-Image is only shown as long as the post is still up. (If you remove the unlisted post, the image is no longer hidden.) This could cause you to have a ton of extra unlisted posts that you cannot delete. (even if you host three images per post, extrapolating on the current method I use)
-Significantly more complicated.
-Not usable for clickable links that will bring you to a picture. (It either brings you to an error page, or makes you download the image, neither of which are helpful.) You have to give someone else access to your recent unlisted post to do that, but it does not work well. It really has to be in a forum or a planes description.
-Image must be in the same rectangle shape as the thumbnail of a plane is.

Anyway, I hope this was interesting for you!