2.15 Optimize images for sustainability

Materials: High
Energy: High
Water: High
Emissions: High

Ensure images, if required, are optimized, correctly formatted, and sized, with lazy loading as appropriate, and are managed effectively.

Need for images: Machine-testable
Do not include images unless they provide positive value. Consider the quantity, format, and sizes required.
Optimized images: Machine-testable
Resize, optimize, and compress each image. Provide images in appropriate sizes for different screen resolutions.
Lazy loading: Machine-testable
Include lazy loading to ensure images only load when they are required.
Sizing and deactivation: Machine-testable
Provide the option for images to be disabled or provide a low-fidelity alternative.
Image management and use: Machine-testable
Set up a media management and use policy to reduce the overall impact of images. Include criteria for media compression and file formats.

Economic
Optimizing resources means users with data caps can preserve their resources. Providers can enjoy reduced hosting costs due to less data being transferred.
Environment
Compressing and delivering images in lightweight formats can reduce the hardware burden on older devices. This can reduce overall consumer e-waste by slowing or eliminating forced upgrade cycles.
Performance
Optimizing images can accelerate performance by reducing HTTP requests, data transfer, and the physical rendering effort. All of these have an impact on user experience and performance.
Social Equity
Providing lightweight images makes it easier for users in low-bandwidth areas or those using older devices to access your content, provided these devices can support the formats used.