Deleting a pinned thumbnail

[jstarr]

deleting a pinned thumbnail on the new tab page does not remove the pinned status and thus this site will no long be added when revisiting the site, it can only be added via dragging from bookmarks again
once added from bookmarks it will still have its pinned status

[dfoulkes]

You might want to list the 'exact' steps that you are taking... I read your post but I'm not sure what you mean... plus, maybe a screen-shot of the final result.

See: Posting_a_screenshot_on_the_forum.
Posting a screenshot on the forum - MozillaZine Knowledge Base
Use a compressed image format like .png or .jpg and please do not post large images that break the forum layout, use thumbnails instead or only post a link.
If you need a place to host a screenshot... Note the "Uploading for general use" section of the document.