Conciseness

Quick Reference, Check, and Fix are tight and information-dense, but the "Explain" section spends several sentences on concepts Claude already knows ("JPEG compression works by converting pixel data to frequency components (DCT)", PNG DEFLATE, what EXIF metadata is, how progressive JPEG behaves). Fits anchor 3 ('mostly efficient but includes some unnecessary explanation'), not 2 (padding is confined to one section) and not 4 (that section is textbook material with no skill-specific value).

Actionability

Very concrete tool-plus-parameter guidance: "re-encode with mozjpeg at quality 80 with progressive=true", "pngquant at quality 65-80", "AVIF: encode at quality 60 with effort 6", "run through SVGO", plus a named Lighthouse audit with a 4KB threshold. Not 5 because no literal copy-paste commands are given (CLI syntax for mozjpeg/pngquant/SVGO is left to construct), not 3 because the guidance is specific and executable, far beyond pseudocode.

Workflow Clarity

Check → Fix → Report sequence is present ("Report each image with its current size and estimated savings", "show the before/after file size and percentage reduction"), but the Fix step is a batch, destructive re-encode of originals with no explicit validation checkpoint — no re-run of Lighthouse to confirm savings, no visual-quality verification, no guidance to preserve originals. Per the batch/destructive feedback-loop cap, workflow clarity is capped at 3.

Progressive Disclosure

~45-line body with well-organized sections (Quick Reference, Check, Fix, Explain, Code Review) and a single clearly signaled, verified one-level-deep reference: "For full implementation details, code examples, and framework-specific guidance, see `references/rule.md`" (the file exists and itself contains no nested references). Matches anchor 5 for a compact skill with a clean pointer.

Specificity

Lists several concrete actions — "Check encoded size, rendered size, loading strategy, and above-the-fold impact together" plus "reviewing image assets, markup, and CDN or build transforms" — but coverage has minor gaps (no format-level actions like EXIF stripping or per-format compression mentioned). Fits anchor 4 ('several specific actions; minor gaps'), not 5 (not comprehensive) and better than 3 (more than 1-2 actions).

Completeness

Both parts are explicit: 'what' = "Check encoded size, rendered size, loading strategy, and above-the-fold impact together"; 'when' = "Use when reviewing image assets, markup, and CDN or build transforms related to Optimise images for faster loading". Not 5 because the 'when' clause is anchored to the rule title rather than concrete user-intent trigger phrases, making it slightly circular; well above 3 since both are clearly present.

Trigger Term Quality

Good natural keyword coverage: "image assets", "markup", "CDN or build transforms", "Optimise images for faster loading". Not 5 because common synonyms and file extensions are missing ("compress images", "optimize"/US spelling, ".jpg", ".png", ".webp", "Lighthouse"); better than 3 since several natural terms a user would actually say are present.

Distinctiveness Conflict Risk

Clear niche (image optimization review for web delivery) with distinct trigger surface (encoded size, rendered size, above-the-fold impact). Not 5 because "loading strategy" overlaps with sibling skills like lazy-loading or responsive-image rules; more distinct than anchor 3's generic overlap risk.