Aglet

How to diagnose image weight that delays useful content

An image can slow a page through transfer, decode, layout, or competition with the content needed for the first action. This triage guide identifies which images matter to the initial view, compares their delivered and intrinsic sizes, and finds the first measurable delay.

Establish what is happening

  1. List images in the first useful view

    Capture route, viewport, connection profile, image URL or stable asset name, displayed dimensions, intrinsic dimensions, encoded bytes, decoded memory, and loading order. Mark whether each image is essential to understanding or only decorative. Record first useful content and interaction readiness.

  2. Separate transfer, decode, and layout cost

    Align request timing, response completion, decode, style recalculation, layout, paint, and first action. Compare the image waterfall with a run where below-action images are absent or delayed. Keep the comparison controlled so a faster result does not hide a missing visual required for context.

  3. Compare responsive and cache states

    Repeat at a narrow and wide viewport with cold and returning cache states. Check whether delivered dimensions match display needs and whether the same asset is downloaded more than once. Note which image or state creates the first divergence rather than blaming total page bytes.

What to carry forward

Return a scope statement naming the image or group, first measurable cost, viewport and cache conditions, and visual role. Route the next work to asset bytes, decode, loading order, or layout. Stop when evidence identifies one bounded image change and the content that must remain visible.

Keep the decision with the work.

Use a Work Item in Aglet to record the problem, the evidence you have, and the next decision. Add an owner and priority, then keep updates in the discussion so the next person can follow the reasoning.

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