What the LinkedIn banner maker does
The banner maker draws a LinkedIn profile banner from your words and a background colour, and saves it as a PNG at exactly 1584 x 396 pixels, the size LinkedIn asks for. Type a headline, add a supporting line if you want one, pick a colour and choose where the text sits.
It's free to use and works in your browser, without an account. The text turns ink or white on its own, whichever reads better on the colour you picked.