@tonyr - I am really thrilled to see you taking up this community engagement challenge.

Of course we're here to help! As I was mentioning to @karenmckersie - 300 words minimum per post is not a lot. Heck, your comment here is nearly half that. LOL

Crediting images:
There are different ways to do this. I personally like to include the image source link after the photo.
Some people compile their links and post them at the bottom of their post.
All of your images should either be your own, or specifically public domain, or creative commons (whatever attributes the image requires). The very important reason for this is because some content is copyright material and can only be used with express written consent. Unfortunately a lot of people don't realize they can be severely fined if they're caught and it jeopardizes the whole site, especially if there is a DMCA claim against you. Bear in mind this is not limited to just Steemit, but it's appropriate for any platform where sharing content occurs.

Oh, I hope I didn't scare you with all that but it is an important warning to do the right thing all the time. Knowledge is Power.

Good luck with this challenge and don't forget to keep us up to date with your progress. :)