The incbin directive includes file verbatim at the current location. You can control the search paths used with the -I command-line option (refer to Chapter 3 Command-Line Options). Quotation marks are required around file.
The skip argument skips a number of bytes from the start of the file. The count argument indicates the maximum number of bytes to read. Note that the data is not aligned in any way, so it is the user's responsibility to make sure that proper alignment is provided both before and after the incbin directive.