This article has some good information on using pictures in your blog posts.
https://steemit.com/steemit/@profitgenerator/how-to-use-pictures-on-steemit
For contests like these though, you must use your own work though and not work from another source, which means that it should be an image that you take yourself using your camera. I hope that his will help you in the future.
Nice @derangedvisions