FLUX.2 Klein is an image generation model built for speed, and this site lets you try it and read its documentation. It comes in two sizes. The 4B version carries an Apache 2.0 licence and can run on consumer graphics cards, while the 9B version aims for higher quality.
The site says images can be produced in less than one second. You can start generating directly in the browser, or download the open model to run on your own hardware if you have a suitable GPU.