When logging in/out using CentralAuth miniatures of all of the project logos are displayed. Like below
For Wiktionary the icon is this one.
Suggestion: Change the icon to a miniature of Wiktionary-logo.svg.
For Wikidata the icon is this one. It is the only one of all of the logos to include the project name as text.
Suggestion: Use a square version of Wikidata-logo.svg instead.
For Wikinews the icon is this one. Since it is not square it gets horizontally squashed in CentralAuth though making it almost unrecognisable.
Suggestion: Make it square by adding white-space above and below.
Same as for Wikinews albeit less extreme.