Welcome, you can also just right click on a photo (make sure its not bigger that 600x600) copy and paste right into the box without using the editor. That's how people do it on comments where you see pics, to make sure it sticks click the raw html you should see it in the preview. Here is one of my posts for your upvoting pleasure _theres an ass hat running a bot downvoting every post that comes up. Follow the post to my page, there's lots more info on one of my posts with an error message about pics Blessed Be
https://steemit.com/steem/@kalaylah77/isaac-asimov-how-do-we-stop-a-habitual-downvoter-he-obviously-is-being-paid-to-push-worthy-content-to-the-back-so-certain-posts