use a sane-sized image here

[aschweigert]

for http://jira.inn.org/browse/RNS-156

This should not be the full sized image (obviously). The rectangular thumb seems to work but I'd want to test this a bit and make sure that's the best size/crop to use to here

[benlk]

rect_thumb is max 800x600, and crops to fix the 4:3 aspect ratio.

The two oddly-large images I see on that site's news category are:

• /wp-content/uploads/2015/09/RNS-MUSLIM-AIRLINE080815.jpg, which is resized to 800x600
• /wp-content/uploads/2015/09/thumbRNS-KENTUCKY-CLERK090315a.jpg, which is resized to 533x600

I tested this on vagrant by uploading those two images (the unresized versions linked above) to a site already running this Largo, and while the image for the homepage featured image remained oddly large, visually, it wasn't full-resolution, so that's good. This PR succeeds.

We should make this image smaller: https://github.com/INN/Largo/blob/master/partials/archive-category-secondary-feature.php#L5 It never gets wider than 273px in desktop or mobile views, so we can easily use a smaller-sized thumbnail there.

[benlk]

Using http://nonprofitquarterly-org.largoproject.staging.wpengine.com/category/management/ as a test, this looks good to go.

[aschweigert]

the content partial is also used in the river on the homepage which means (I think) that it will sometimes be as wide as 768px so 800px probably does make sense