Welcome to steemit!
When you have external sites you intend to post content from it is best to verify that the content is yours. You can simply create an entry on any one site such as facebook.com mentioning steemit and then provide a link to it.
I suggest adding a link to the external page to your steemit.com profile. It prevents answering the question of whether the content is yours in the future. Consider cross linking the same content in your posts, cross-linking also tends to drive more traffic both ways.
Photography is pretty popular here. I hope you enjoy being part of the steemit community! @jamtaylor runs a weekly photochallenge you might enjoy.