The toolbar button image is generated via the CSS Sprite Generator, with custom settings of 'Horizontal Offset: 0.0px' and 'Vertical Offset: 0.0px'. The image is then manually converted from True Color to 256 with transparency.
Tango icons from the Tango Desktop Project. Additional Tango icons from Jimmacs' Tango OpenOffice
Silk icons are created by Mark James from famfamfam.com.