1. Why You Need a Mobile Image Checklist
Mobile users demand higher page loading speed and visual experience. An unoptimized image can slow down the page, disrupt layout, and even affect user retention. Therefore, creating a mobile image checklist helps website creators and maintainers systematically check image issues in daily work, reducing oversights.
2. Core Dimensions of the Checklist
2.1 Image Size and Resolution
- Check if the maximum image width is suitable for mobile screens (usually no more than 750px).
- Avoid displaying oversized original images directly on mobile; use responsive images or crop as needed.
- Ensure images are not blurry on Retina screens (consider 2x or 3x images, but watch file size).
2.2 Image Format Selection
- Prioritize WebP format (good compatibility, smaller file size) with JPEG/PNG as fallback.
- Use SVG for icons and simple graphics to avoid distortion.
- Use JPEG for photographic images, and PNG or WebP for transparent backgrounds.
2.3 Compression and File Size
- Keep each image file size under 200KB, with key above-the-fold images even smaller.
- Use tools like TinyPNG or ImageOptim for lossless compression.
- Check if any uncompressed original large images are directly referenced.
2.4 Loading Speed and Lazy Loading
- Ensure all below-the-fold images use lazy loading (loading="lazy").
- Check if images block page rendering via Lighthouse testing.
- Consider using a CDN to accelerate image delivery.
2.5 Adaptability and Layout
- Check if images use flexible layouts (e.g., max-width: 100%) to avoid overflow or scrollbars.
- Test display on common phone sizes (iPhone, mainstream Android models).
- Check image behavior during portrait and landscape orientation switches.
2.6 Accessibility and SEO
- Ensure every image has a descriptive alt attribute for search engines and screen readers.
- Use English descriptive image filenames to avoid Chinese garbled characters or meaningless strings.
- Check if images are indexed by search engines (review Robots.txt or meta tags).
3. How to Create the Checklist
Organize the above dimensions into a table or list format, with columns for "Pass/Fail/Notes" for each item. Use online documents or project management tools for team collaboration and updates. Whenever the website is revamped or new images are added, check each item against the list.
4. Important Considerations
The checklist is not a one-time task; it should be updated as mobile devices and browsers evolve. For example, when a new format like AVIF emerges, evaluate whether to include it. Also, avoid over-compressing images to the point of quality loss; find a balance between quality and speed.
5. Summary
Creating a mobile image checklist revolves around six key areas: size, format, compression, loading, adaptability, and accessibility. Systematic checks can effectively reduce mobile image issues and enhance overall website experience. Regularly review the checklist and optimize based on user feedback and performance data.
