Hi,
Some articles/links are not being shared properly.
Example: http://triathlon.competitor.com/2015/12/training/4-off-season-cycling-rules_126831
is not pulling an image in, but others are.
I have used the validator tool https://cards-dev.twitter.com/validator
Everything validates, robots.txt file is obviously working since other images appear in other links.
I tried to resize the image in the sample above but still nothing.
Another attempt to fix it was switching between summary_large_image to just summary but no fix yet.
In the card example of this link it all works out fine, even with a slightly larger image as the twitter:image meta tag.
Any ideas what could be causing the lack of image on the first example (not the only link that does not generate the card with image properly on the site)