resize-for-banner

Rescale an image into social banner versions using ImageMagick. The image is resized to fit and the leftover space is padded black — never cropped. Use when the user wants a banner, cover photo, or resized version for a social profile or article header. Never overwrites the original — creates new files beside it. Defaults to Twitter/X (5:2, 1500x600); other platforms available on request.