Two independent causes, both silent:
LimitedBody returned an error once the cap was hit, so scrapeOG failed the
whole goquery parse on any page over 2 MiB — even though og: tags live in
<head>, near the top. Hitting the cap is a truncation, not a failure: return
io.EOF and let the parser decide whether it found what it needed. Sized
against the pages actually posted here (n=14): og:title landed within the
first 7 KiB on twelve, worst case ~600 KiB.
validateImageURL HEAD-probed the image and bailed on non-200. Some publisher
CDNs (dims.apnews.com among them) answer HEAD with 403 while serving the same
URL over GET, so their thumbnails were always dropped. Probe with HEAD first,
fall back to a ranged GET asking for the first KiB. A 206 declares the full
size in Content-Range's "/119070" suffix rather than Content-Length, so the
tracking-pixel filter reads size from there.
