Your count is up to you. There is no minimum beyond what you decide. But Big Buddy will be watching you! If you pledge 100 words/images, then every 6 days chime in to tell us that you've produced 20% of them.
This is not words to be done in lieu of something else. If you have a bingo, or a big bang, or a drabble-a-day, it all counts! Words/images do not have to be posted to count, they just have to be done!