- Tap on save on any cell w/ a save button (currently only in the "more like" lists and non-nearby feed items)
- Go to saved pages
The thumbnail I see in the feed is also present on saved pages
The saved page cell has no thumbnail.
This is because there's no MWKArticle w/ a thumbnail/lead image to use for the saved page's thumbnail. Previously the only way to save a page was by visiting it, but this is no longer the case.
Observe article download notifications, and reload any visible cells related to the title which was saved. See WMFArticleContainerViewController for observation code, and modifying WMFArticleListCollectionViewControllerto make the same observations and update its cells. This supersedes the denormalization approach due to simplicity & comprehensiveness (also includes extracts & entity descriptions).
Denormalization approach (deprecated)
Add a thumbnailURL property to saved page entries, and add it as a required property when saving a page. IOW, you can only add a saved page entry if you have both a MWKTitle and a thumbnail URL. We can lazily migrate existing saved page data by copying existing article thumbnails when the saved page list is created (i.e. no need to do a startup-blocking migration).