Adam Williamson wrote:
The short version of what you should do is, at a minimum, put a
48x48
version of the icon in /usr/share/icons/hicolor/48x48 . It's really good
to put a .svg version of the icon in /usr/share/icons/hicolor/scalable
too, and what with GNOME using very large icons on its overview now,
it's really desirable to provide a 128x128, 192x192 or even 256x256
version too. Of course, it all depends what sizes and formats are
available from upstream.
It's also nice to have smaller versions, especially if the larger versions
have a lot of detail and thus don't scale down well. The KDE Plasma Kickoff
menu (the default) uses 32×32 icons, the KDE Plasma classic menu uses 16×16
icons.
If you provide only one size, that size will get scaled up or down as
needed, which may or may not look OK.
Kevin Kofler