Classify images by their role
A hero image, an immediately visible project screenshot and a thumbnail far down an archive do not have the same loading needs. Defer images that are not needed for the initial view, while keeping important above-the-fold content discoverable promptly. Adding lazy loading to every image is a mechanical rule that can delay the very content a visitor is waiting to see.
Use the browser’s built-in behavior
For ordinary images, the loading attribute gives the browser a native deferral mechanism. Actual fetching decisions can depend on the browser, connection and distance from the viewport. Treat it as a hint rather than an exact pixel threshold. Prefer the simple built-in approach before introducing a custom observer and placeholder system for a case the browser already handles.
Reserve the eventual dimensions
Provide image dimensions or an appropriate aspect-ratio container so deferred content does not push surrounding text around when it loads. The empty space should reflect the actual intended layout. A placeholder that starts as a short strip and later becomes a tall photograph can still cause movement even though the download was successfully deferred.
Work through a portfolio example
Imagine a project grid that begins beneath the opening introduction. The first visible screenshot may be fetched normally, while later rows use lazy loading. Each screenshot sits inside the same reserved frame. Scroll through the page on a slower connection and check that the headings remain stable and that images arrive before their absence disrupts normal reading.
Avoid content-discovery traps
A deferred image should still have a real source and useful alternative text where appropriate. Do not require a scroll event just to insert the only description of an important project. Custom image effects should leave the content understandable when JavaScript fails or reduced motion is enabled. Loading strategy and decorative animation need separate failure paths.
Measure the actual improvement
Compare initial requests and transferred bytes, then inspect the main content’s loading time and layout stability. Test a direct visit and a deep anchor that opens farther down the page. Confirm that deferral did not break printing or normal navigation for the intended audience. Keep the strategy when it reduces unnecessary early work without making visible content feel late or unstable.
Further reading
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