See the "Chandra Bose" cell below ( From: https://en.wikipedia.org/api/rest_v1/feed/featured/2016/12/01 ):
The problem is the iOS app is only *displaying* the Bose icon at 40x40 pixels.
But we are fetching the following 17K 240px icon:
We really only need to be fetching the following 1K 40px icon:
Fetching 17K when 1K would suffice may not seem like much, but most of the smaller icons in the iOS feed have the same issue, so the effect is compounded.
Once the parent ticket is complete the feed will provide canonical image info for the "tfa", "mostread", and "news" sections images. Then we can safely request exactly needed resolutions because we'll know the max resolution. ( the thumbnailer doesn't like it if you request a width >= the canonical width )
More specifically, we can take the new canonical image url from the feed query results and pass it to WMFChangeImageSourceURLSizePrefix with a retina adjusted size from UIScreen+WMFImageWidth to get images which actually fit.