The discussion revolves around a broken image issue when using onebox to display local content within the forum. limeblast initially reported the issue, providing an example link and HTML code, but techAPJ was unable to reproduce it. However, limeblast pointed out that the issue is visible in the same post on meta.
Mittineague suggested that the issue might be related to external sites, as an internal link worked fine, but an external link from SitePoint showed a broken image. limeblast confirmed this by providing another example of a broken image from an external site.
techAPJ was eventually able to reproduce the issue on the latest Firefox and techAPJ fixed the problem with a commit to the onebox repository on GitHub.