I'm sorry I don't know how to add pictures(Can someone tell me?)
Geekhack won't display .WEBP image files, so that might be why you are having trouble.
I put a .PDF of your picture in postimage to get a URL link. Then I put that link in this message with img commands at the front and back. Like this except with [ ] instead of ( )
(img)https://i.postimg.cc/6tV5ZW4y/Asiimov-base.png(/img)

If you look at the exact text of this message (for example by using Quote), note that Geekhack automatically added image size. You will see (img width=640 height=XXX) even though I only typed (img)
If you want a different size, change the value of one dimension and delete the other one, for example (img width=400)
Geekhack automatically calculates the other dimension to keep 1:1. Whenever you revise your post with a new picture link, delete one or both dimensions or the new picture will probably be stretched.
I hope this is helpful!