How I publish my Picoronn game here?

I need make a png file? How?

Here is a link to the relevant section of the manual.
https://www.lexaloffle.com/dl/docs/picotron_manual.html#Uploading_a_Cartridge_to_the_BBS

Thanks. I post it.

https://www.lexaloffle.com/bbs/?tid=142191