Little Card Editor loves both Facebook and Twitter. You can choose to send to one or both, and which plaform's username is displayed in the menu bar.
It has been suggested that the cards look better with no text in the tweet. Of course that makes it hard to search for the cards. Your choice. :-)
You can choose a logo from this set of Emoji characters.
The canvas is 800 pixels wide by 600 tall. If your image isn't proportional, we'll add blank space above and below. If you'd rather have the image stretch to fill the canvas, check the box.