Select an asciinema cast file, configure options, then click Render to generate an animated GIF.
The animated GIF can be saved by using your browser’s Save Image As... functionality, invoked by right-clicking the image.
Oversized images are scaled down to fit on the screen. Saving retains the full resolution.
Browsers throttle background tabs, so be sure to keep this page in the foreground during rendering to prevent a pause.