react-doctor/nextjs-image-missing-sizes
Add sizes for responsive behavior: `sizes="(max-width: 768px) 100vw, 50vw"` matching your layout breakpoints
- Status
- Active
- Category
- Next.js
- Assessment
- Evidence-required risk
- Required evidence
- source code
- Default configuration
- Enabled
- Default severity
- warn
Show technical metadata
- Scope
- Next.js
- Active when
- framework=nextjs and capabilities=nextjs
- Requirements
- nextjs
- Tags
- test-noise
- Priority
- 50 (P2)
- Source
- oxlint-plugin-react-doctor
- Rule set
- oxlint-plugin-react-doctor 0.9.3 (prompt schema 2)
Validation prompt
Confirm the detector match and collect the required evidence before deciding whether an edit is warranted.
Flags a JSX element named Image with the fill prop but no sizes prop. False positive if Image is a custom component rather than next/image: check the import. Also low-impact when the image renders at a fixed pixel size since the browser still picks a sensible source.
Evidence boundary
The diagnostic proves only that the detector’s modeled source pattern matched. It does not prove runtime impact, product intent, rendered failure, or that one remediation is correct.
Establish the environment, repository policy, exceptions, and required rendered or runtime evidence before deciding the occurrence.
Record one outcome:
- Confirmed failure: The required evidence establishes the violation.
- Rejected: A documented exception or false-positive predicate applies.
- Needs evidence: Named evidence can still be collected.
- Unavailable: Required evidence cannot be collected in this run.
- Waived with evidence: An authorized, scoped exception applies to an established failure.
- Observation: The review records an optional tradeoff without claiming a defect.
A waiver records its scope, authority, evidence, and review condition. It is not a pass or false positive.
Default severity is registry metadata. Use the occurrence’s JSON severity after repository configuration when ordering real findings.
Fix prompt
Apply this candidate correction only after the required evidence confirms the risk.
Add a sizes prop matching your layout breakpoints, e.g. sizes="(max-width: 768px) 100vw, (max-width: 1200px) 50vw, 33vw". Without it Next.js falls back to 100vw and the browser downloads the largest source from the generated srcset. https://nextjs.org/docs/app/api-reference/components/image#sizes
Repository-wide copy prompt
Use this repository-wide prompt only after validating each occurrence. For one occurrence, use the guidance above.
Show repository-wide prompt
Fix every confirmed react-doctor/nextjs-image-missing-sizes diagnostic in the current repository.
Required change:
- Add a sizes prop matching your layout breakpoints, e.g. sizes="(max-width: 768px) 100vw, (max-width: 1200px) 50vw, 33vw". Without it Next.js falls back to 100vw and the browser downloads the largest source from the generated srcset. https://nextjs.org/docs/app/api-reference/components/image#sizes.
Validation before editing:
Flags a JSX element named Image with the fill prop but no sizes prop. False positive if Image is a custom component rather than next/image: check the import. Also low-impact when the image renders at a fixed pixel size since the browser still picks a sensible source.
Constraints:
- Make the smallest change that fixes the root cause.
- Preserve behavior and interfaces unrelated to this diagnostic.
- Reuse existing project components, utilities, and conventions.
- Do not introduce render-phase side effects, render-phase state updates, or Hooks rule violations.
- Adapt identifiers and framework details instead of copying blindly.
- Do not disable the rule or suppress matching code.
- Confirm this rule is enabled for the project:
framework=nextjs and capabilities=nextjs.
Assessment:
- Record detector evidence, applicability facts, assumptions, missing evidence, and the rule class for this occurrence.
- Return one outcome: Confirmed failure, Rejected, Needs evidence, Unavailable, Waived with evidence, or Observation.
- A waiver records the established failure, scope, authority, evidence, and review or expiry condition. It is not a pass or false positive.
Verification:
- Run focused tests for the changed behavior.
- Run React Doctor and confirm this diagnostic no longer appears from changed code.
- Run an unfiltered scan of the affected scope before claiming no cross-category regression.
- Report the files changed and any checks you could not run.