Either import or draw your bitmap.
For using the bitmaps with the matrix, you have to rotate it clockwise 90°.
Save it as X-Bitmap, don’t check the X10 option.
Then open the xbm file with an editor, insert after “static unsigned char” PROGMEM, e.g. “static unsigned char PROGMEM Jahr2_bits =” instead of “static unsigned char Jahr2_bits =”.
Copy the whole text after “static..” into your Arduino file, you can now call it with ht1632_putbigbitmap( or derivatives of them, you need only to know the number of lines in width and height. Add an alphabetic char to the name of the bitmap if you have a bitmap with only a number as name