I've reverse searched a few of the photos submitted in the photography category and found they were just stolen from other sites. Before upvoting any photos, please do a reverse image search and make sure they're not stolen. Steemit is getting more and more popular and people are uploading whatever photos they can to try and make money.
If you find a cool photo that you just want to share, make sure you put a link to the source. Don't try to pass it off as your own.
If you use Google Chrome, simply right click on the image and choose "Search Google for Image". If not, go to http://images.google.com and click the grey camera icon on the right side of the text box.