{"template":{"name":"instagram-slideshow","description":"Instagram slideshow portrait card (9:16) with fullscreen photo and bottom caption source area.","aspect_ratio":"9:16","placeholders":[{"key":"accent_color","description":"Accent/highlight color (hex/rgb/hsl)."},{"key":"bg_color","description":"Background color (hex/rgb/hsl)."},{"key":"bg_image_url","description":"Background image URL rendered fullscreen."},{"key":"height","description":"Output image height in pixels."},{"key":"source_image","description":"Source credit for the background image."},{"key":"source_post","description":"Source reference for the post/news content."},{"key":"subtitle","description":"Supporting subtitle or body text."},{"key":"text_color","description":"Primary text color (hex/rgb/hsl)."},{"key":"title","description":"Main title text shown prominently."},{"key":"username","description":"Account username displayed in the top area."},{"key":"width","description":"Output image width in pixels."}]}}