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That all info I already know. I am sorry to say that your that big post was duplicate (These type of post were already created). In half post you are explaing imgur to me, that I already know. Might be I like to categorize your post as merit shitpost. Big , graphical but still not addressing the real question.
Refrain yourself from using bold and big fonts and try to understand issue carefully.
Thanks Omega and sncc, I was missing the extension part
In the short, the image URL must finish with the extension. (.jpg, .png, .gif etc.) In your case, just right click and copy the link from imgur.
You are using the link to imgur, but to embed the image you need the link to the image itself. Clicking your image in imgur, you can see several links at the right of your image. You can then copy the link for "BBCode" or "Linked BBCode" and paste it in your post.