How on earth do I share captures on Twitter?

Sorry if this is somewhat off-topic for the forum. I’ve been taking loads of pics in Forza 7 and really want to share them somewhere other than my Xbox profile. I’ve had a Twitter account for ages but never really used it, so I thought that would be a good place. I can make it a social account completely dedicated to gaming stuff. But whenever I use the ‘share to Twitter’ function from Xbox One or Forza Hub, it just posts a link. Once have I managed to post a picture directly, and I have no idea how I did it. I don’t necessarily think loads of people are going to want to see my pictures; I’d just like an easy-access, convenient place for me to scroll through them while giving the good pics a chance for a wider audience, if I ever take any. Any help will be greatly appreciated.

And yes, I do feel incredibly old having to ask how to use social media!

Edit: Here is my Twitter. As you can see, one Sonic Mania picture but otherwise, links links links.

Download them from Forza Hub and then upload them via the Add Media option in twitter, it will pop a window up in which you can search your images.