Yeah, the browser version is kinda weird. I think you can drag and drop pics now though. If you are using a 3rd party storage and want to insert the link, you can do that also. I use imgur, and you just have to be sure to get the markdown link.
You can also try eSteem for mobile on iOS and Android.
Busy.org also makes posting to steemit easier imo. You just login with your steemit account, it may ask for a different password, rather than your main password. Kinda like the posting key, or active key. You can find those in the wallet tab under permissions. You have to click to show the private key because the public key shows by default.
It's a little learning curve for the pics, but once you get it down it's easy. I think they need to make the process much easier like FB, Twitter or IG, and I'm sure they will.