use highest quality image when fetching youtube thumbnails

[tanyaparker]

Before
After

[breville]

We should definitely keep an eye out for any side effects, but seems like a good upgrade.

[wjordan]

sounds good to me if we think the quality upgrade is worth the increase in file-size.

If so, would we want to update

code-dot-org/bin/cron/fetch_external_resources

Line 15 in ca39a5d

results[dashboard_dir('public', 'c', 'video_thumbnails', "#{i[:id]}.jpg")] = "http://img.youtube.com/vi/#{i[:youtube_code]}/mqdefault.jpg"

as well?

[tanyaparker]

I say let's try moving the pendulum a little more in the direction of better quality/bigger file size. I think this particular change is worth it. And as we keep tabs on performance, we can decide if we need to revert.