Hehe, nice
Okay, so I am assuming this is for the identity(5 command? If so, you will need to know how to convert binary to hex which isn't too difficult. Each hex digit is 4 bits or pixels. So for the byte on the screen 01111110, we get the first pixel off followed by 6 pixels on and then a pixel off. Convert this to hex and you have "7E" as a more compressed form
However, if you want an easier. If you want to make a sprite that is two bytes wide and 3 pixels tall:
01111111 11111110 = 7F FE
10000000 00000001 = 80 01
01111111 11111110 = 7F FE
So we would use the code "7FFE80017FFE" for the picture
You can likewise apply this to wider and taller sprites, however for a sprite that large, it is better to just use a picture. You can use the xLIB functions of Celtic 3 to make hacked pictures (I think they are real(3 and real(9)
I hope this helps?
EDIT: I used to code a lot with Celtic 3, so I know I have the readme somewhere on my computer. Hopefully next time I will be able to give a better answer