**Main goal**: Choose a sensible set of thumbnail sizes to offer in Special:Preferences. We should have fewer, carefully chosen options. Our choices should provide the maximum utility for different types of users (e.g., small size for people with low bandwidth and large size for people with high pixel density) while also being efficient with disk space and performance.
**Current status**: https://noc.wikimedia.org/conf/highlight.php?file=InitialiseSettings.php says (as of July 2015):
'wgThumbLimits' => array(
'default' => array( 120, 150, 180, 200, 220, 250, 300, 400 ),
'+itwikiquote' => array( 360 ),
'svwiki' => array( 120, 200, 250, 300, 360 ),
),
MediaViewer uses these sizes: 320, 800, 1024, 1280, 1920, 2560, 2880
Because of retina support, we effectively support three times as many sizes as it looks like (at least for smaller ones):
120 => 120, 180, 240
150 => 150, 225, 300
180 => 180, 270, 360
200 => 200, 300, 400
220 => 220, 330, 440
250 => 250, 375, 500
300 => 300, 450, 600