[Mediawiki-l] Why Facebook and others can't see a wiki's most important image

Daniel Friesen lists at nadir-seen-fire.com
Sun Jul 24 05:15:11 UTC 2011

On 11-07-23 09:21 PM, K. Peachey wrote:
> On Sun, Jul 24, 2011 at 2:17 PM,  <jidanni at jidanni.org> wrote:
>> Ha Ha, Ha Ha, told you so *for years*. Now when anybody quotes a
>> MediaWiki article on Facebook, there is a 95% chance it will look bad...
>> serves you all right! Plus (Google+? Dare not also test it there to see
>> what happens), it is NOT a Facebook bug. Ho Ho Ho. Muhahaha.
> How is this not a facebook bug? It doesn't scan the page properly for
> a list of possible images to choose from?
Facebook scans the <img> tags on a page for images that are at least
50x50px with a max aspect ratio of 3:1.
When you try to share a url for a Wikipedia article with a good set of
images you'll get a selection of images to pick from. Of course an
article without any images won't have any to pick from and FB will just
use no image. It does trip up on some of the templates the Wikipedia
community uses, some of which embed some icons at sizes slightly larger
than 50x50px causing FB to include those.
The logo is an embedded background-image so it doesn't show up in the scan.

jidanni seams to have the opinion that the logo of a wiki is so
important that a user with a text browser that can't see images would
like to see something like "[site logo here]" to indicate that the site
has a logo they can't even see.

jidanni isn't particularly good at calmly presenting a problem in a way
that would get people to see what pieces are broken and get people to
chime in on ways to fix them. Rather he seams to think that insulting
the people he's trying to get to change something will help, rather than
cause them to simply dismiss him as a jackass and miss the few valid
points of his cause counterproductively making it even less likely what
he's trying to get changed will be changed.
He might also want to take a look at the flash based sites out there
before he tries to argue that MW which is built with a number of
features to permit accessibility for screen readers and text browsers
was built by people with no knowledge of how screen readers and search
engines work.

Looking over things. Our powered by icons and whatnot make use of <img>
tags. Sadly while the background-image trick could hide them I don't
believe it would work since that'll break the accessibility there since
the background-image trick can't replicate the alt text, least not
without having negative quirks while images are still loading. Screen
reader and search engine wise the <img> would be correct here.
The logo uses a background-image. It's not a static pre-bundled image
like the powered by icons. In this case, I believe that the function of
using the background-image rather than an <img> with an alt or an empty
alt="" is to prevent overly large logos (we don't have a standard logo
size, and the sizes that skins use actually vary) from overflowing out
of the logo area and obscuring the page content.

~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]

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