tool-bar-local-item

tool-bar-local-item is an autoloaded compiled Lisp function in `tool-bar.el'.

(tool-bar-local-item ICON DEF KEY MAP &rest PROPS)

Add an item to the tool bar in map MAP.
ICON names the image, DEF is the key definition and KEY is a symbol
for the fake function key in the menu keymap. Remaining arguments
PROPS are additional items to add to the menu item specification. See
Info node `(elisp)Tool Bar'. Items are added from left to right.

ICON is the base name of a file containing the image to use. The
function will first try to use low-color/ICON.xpm if `display-color-cells'
is less or equal to 256, then ICON.xpm, then ICON.pbm, and finally
ICON.xbm, using `find-image'.