One of the nice things about using Ello is the lack of limits. There's no 140 character limit like with Twitter, and you can upload images to accompany your post (of whatever length you choose). Here's how to add an image to an Ello post:
First, add your text in the box at the top of the page, then hover over the "Files" icon below the post box (it looks like two pieces of paper). You'll see it expands to say Upload:
Ello post without an image...yet.
You'll get the standard file selection sheet, so find your file and click Choose. Then it becomes a second item in your post. You can have as many as you like. Once you have your text and image set up, you can hit the arrow in the lower right to post your text and image. Here's the finished product, with an image courtesy of Louie Mantia:
Kelly's finished post in Jeff's timeline. Image courtesy of Louie Mantia.
It doesn't matter to Ello what order you add text and images, so it's your call if you want the text to show above or below the image you added.
You can also drag and drop images into the post box if you have enough screen real estate that it is possible to drag into your browser window from a Finder window. And if you need more than one, just hit the upload button again and add as many as you like (or at least, I quit counting once I got past ten).