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Get Started Free →Use when reviewing image assets, markup, and CDN or build transforms related to Use descriptive image filenames. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
.claude/skills/thedaviddias-filename-quality/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-01 | ✗→✓ | ▲ Improved | 7% | 0% |
| case-04 | ✗→✓ | ▲ Improved | 45% | 0% |
| case-15 | ✗→✓ | ▲ Improved | 62% | 0% |
| case-17 | ✗→✓ | ▲ Improved | 174% | 0% |
| case-18 | ✗→✓ | ▲ Improved | -4% | 0% |
Google explicitly recommends descriptive filenames in its Image SEO best practices. A file named red-leather-wallet.jpg gives search engines context about the image content, improving discoverability in image search. Generic filenames waste this SEO signal. Descriptive names also help developers maintain large asset libraries without opening every file to identify its content.
hero-homepage-team-collaboration.jpgimage1.jpg, photo.png, or camera defaults like IMG_4532.jpgScan all image file references in this codebase (<img src>, CSS url(), import statements, and public/assets directories). Identify filenames that: 1) Use auto-generated names (e.g., IMG_1234.jpg, DSC_0056.png, screenshot-2024-01-01.png). 2) Use meaningless names (e.g., image1.jpg, photo.png, pic.jpg). 3) Contain spaces (e.g., 'my photo.jpg'). 4) Use underscores as word separators (e.g., hero_image.jpg instead of hero-image.jpg). 5) Mix uppercase and lowercase letters. Report each problematic filename with its path.
Rename image files with descriptive, SEO-friendly names: 1) Replace generic names with descriptive ones reflecting the content (e.g., rename IMG_1234.jpg to blue-running-shoes-side-view.jpg). 2) Use lowercase letters only. 3) Replace spaces and underscores with hyphens. 4) Keep names concise but meaningful—3 to 5 words is ideal. 5) Update all references to the renamed file in HTML, CSS, and JavaScript. For large-scale renames, provide a migration script that reads old paths, generates new names, and updates all references.
Explain why descriptive filenames matter for image SEO. Google explicitly states it uses filename as a signal for image search ranking. A filename like product-red-leather-wallet.jpg gives Google context about the image before it even analyses the pixels. Generic filenames (image1.jpg, photo.png) provide no signal. Additionally, descriptive filenames improve developer experience—team members can understand what an asset is without opening it.
Review image assets, markup, and delivery configuration related to Use descriptive image filenames. Flag exact files or components where format choice, sizing, or loading behavior violates the rule, and describe how to confirm the fix in DevTools.
For full implementation details, code examples, and framework-specific guidance, see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/images/filename-quality
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-01 | fail→pass | 15,184 | 13,218 | -13% | 1 | 1 | 0% | 2,976 | 3,179 | +7% | 0 | 0 | — |
case-02 | fail→fail | 7,501 | 2,266 | -70% | 1 | 1 | 0% | 1,396 | 777 | -44% | 0 | 0 | — |
case-03 | pass→pass | 12,735 | 9,213 | -28% | 1 | 1 | 0% | 2,442 | 2,472 | +1% | 0 | 0 | — |
case-04 | fail→pass | 10,372 | 11,769 | +13% | 1 | 1 | 0% | 1,910 | 2,771 | +45% | 0 | 0 | — |
case-05 | pass→pass | 8,045 | 8,903 | +11% | 1 | 1 | 0% | 1,550 | 2,350 | +52% | 0 | 0 | — |
case-06 | pass→pass | 7,382 | 4,194 | -43% | 1 | 1 | 0% | 1,472 | 1,464 | -1% | 0 | 0 | — |
case-07 | pass→pass | 4,802 | 5,246 | +9% | 1 | 1 | 0% | 855 | 1,656 | +94% | 0 | 0 | — |
case-08 | pass→pass | 5,228 | 3,420 | -35% | 1 | 1 | 0% | 1,084 | 1,280 | +18% | 0 | 0 | — |
case-09 | fail→fail | 6,789 | 4,897 | -28% | 1 | 1 | 0% | 1,276 | 1,463 | +15% | 0 | 0 | — |
case-10 | pass→pass | 9,042 | 5,096 | -44% | 1 | 1 | 0% | 1,579 | 1,634 | +3% | 0 | 0 | — |
case-11 | fail→fail | 12,646 | 8,939 | -29% | 1 | 1 | 0% | 2,091 | 2,554 | +22% | 0 | 0 | — |
case-12 | pass→pass | 16,164 | 15,741 | -3% | 1 | 1 | 0% | 2,551 | 3,173 | +24% | 0 | 0 | — |
case-13 | pass→pass | 19,507 | 15,131 | -22% | 1 | 1 | 0% | 3,614 | 3,574 | -1% | 0 | 0 | — |
case-14 | pass→pass | 10,997 | 8,221 | -25% | 1 | 1 | 0% | 2,014 | 2,076 | +3% | 0 | 0 | — |
case-15 | fail→pass | 6,487 | 11,115 | +71% | 1 | 1 | 0% | 1,274 | 2,058 | +62% | 0 | 0 | — |
case-16 | pass→pass | 10,204 | 7,309 | -28% | 1 | 1 | 0% | 1,758 | 1,841 | +5% | 0 | 0 | — |
case-17 | fail→pass | 3,534 | 3,610 | +2% | 1 | 1 | 0% | 476 | 1,305 | +174% | 0 | 0 | — |
case-18 | fail→pass | 12,423 | 7,699 | -38% | 1 | 1 | 0% | 2,207 | 2,124 | -4% | 0 | 0 | — |
case-19 | pass→pass | 12,560 | 10,919 | -13% | 1 | 1 | 0% | 2,095 | 2,329 | +11% | 0 | 0 | — |
case-20 | pass→pass | 13,353 | 12,162 | -9% | 1 | 1 | 0% | 2,141 | 2,645 | +24% | 0 | 0 | — |
case-21 | pass→pass | 13,580 | 8,036 | -41% | 1 | 1 | 0% | 2,243 | 2,023 | -10% | 0 | 0 | — |
case-22 | pass→pass | 13,554 | 11,007 | -19% | 1 | 1 | 0% | 2,058 | 2,607 | +27% | 0 | 0 | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted, and 21 counted toward the lift figure. The other 1 produced results that are not comparable between the two arms, so they are excluded from the headline rather than averaged into it. The headline lift of +23 percentage points is the difference between those two pass rates over the 21 comparable cases. 1 case got worse with the skill loaded, and it is included in that figure.
Without the skill loaded, the model failed this case. With it loaded, the same prompt on the same model passed. This is one improved case from the latest verified run; every case, including any that regressed, is in the table above.
Other measured skills in the registry, with their headline benchmark lift.