The TB_SETBITMAPSIZE message sets the size of the bitmapped images to be added to a toolbar.
TB_SETBITMAPSIZE
wParam = 0;
lParam = (LPARAM) MAKELONG(dxBitmap, dyBitmap)
Parameters
dxBitmap
Width, in pixels, of the bitmapped images.
dyBitmap
Height, in pixels, of the bitmapped images.
Return Values
Returns TRUE if successful or FALSE otherwise.
Remarks
The size can be set only before adding any bitmaps to the toolbar. If an application does not explicitly set the bitmap size, the size defaults to 16 by 15 pixels.