per https://commons.wikimedia.org/?oldid=165672017 People want larger sizes on $wgImageLimits
This should generally not affect performance, as the larger size would only be rendered if the user specificly clicked on it. Doing
$wgImageLimits = array( '2048', '1536' );
$wgImageLimits = array( '3200', '2400' );
would probably satisfy everyone (?)
Also have to look out for $wgSVGMaxSize which is really set way too low (and has a slightly buggy implementation).