The dokuwiki icon on the install page is loaded from http://wiki.splitbrain.org/_media/wiki:dokuwiki-64.png
(~line 90 in install.php)
This is bad if you install dokuwiki on a localhost withot internet connection.
There already is an icon (the bigger one) in the folder ./data/media/wiki/
It would be nice if you could add dokuwiki-64.png into that folder and update the install.php to load the image from the local directory.