Cost of Oversized JPEG

• Camera-native JPEG kills LCP scores on mobile networks
• Email JPEG over 25 MB rejected by Gmail and Outlook attachment limits
• CDN bandwidth cost scales linearly with JPEG file size
• Oversized JPEG forces unnecessary GPU decode work on low-end devices

JPEG Resize Best Practices

• Match output dimensions to actual display size — never ship 4000px JPEG into a 600px container
• Lock aspect ratio unless cropping is the explicit goal
• Use 2× pixel density for retina-targeted JPEG (Instagram, Apple devices)
• Skip upscaling — Lanczos cannot synthesize detail absent from the source
• Resize once at the end of the pipeline, not in stages