---
phase: 21-fix-image-input-deduplication
plan: 01
type: execute
---

<objective>
Resolve duplicate image saving across input/generated images by unifying the hashing approach.

Purpose: Ensure the deduplication system consistently prevents duplicate files in the generations folder by using the same hashing algorithm everywhere.
Output: Consistent MD5 hashing across all image saving operations.
</objective>

<execution_context>
~/.claude/get-shit-done/workflows/execute-phase.md
~/.claude/get-shit-done/templates/summary.md
</execution_context>

<context>
@.planning/PROJECT.md
@.planning/ROADMAP.md
@.planning/STATE.md

# Key source files:
@src/app/api/save-generation/route.ts
@src/utils/imageStorage.ts

# Prior phase with related hashing decision:
@.planning/phases/13-fix-duplicate-generations/13-01-SUMMARY.md

**Tech stack available:** Next.js 16, Zustand
**Established patterns:** MD5 content hashing for deduplication (Phase 13)

**Issues being addressed:**
1. ~~nano-banana-pro model generates without considering image inputs~~ - RESOLVED (no longer an issue)
2. Input and generated images have duplicate files despite different hashes - need consistent hashing approach

**Root cause:**
- imageStorage.ts uses position-based sampling hash while save-generation uses MD5 - these are incompatible
- Same image saved via different code paths gets different hashes
</context>

<tasks>

<task type="auto">
  <name>Task 1: Unify image hashing to MD5 across all save operations</name>
  <files>src/utils/imageStorage.ts</files>
  <action>
Replace the position-based sampling hash in imageStorage.ts with MD5 content hashing (matching save-generation/route.ts pattern).

The current approach at line 209-211 uses a weak hash based on string length and sampled substrings:
```
const hash = `${folder}-${len}-${imageData.substring(50, 100)}-${imageData.substring(mid, mid + 50)}-${imageData.substring(Math.max(0, len - 50))}`;
```

This is problematic because:
1. Different hash method than save-generation API (MD5)
2. Same image can get different hashes if saved via different paths
3. Position-based sampling is weak for dedup (similar images may have same samples)

Replace with:
1. Import crypto at top: `import crypto from "crypto";`
2. Create helper: `function computeContentHash(data: string): string { return crypto.createHash("md5").update(data).digest("hex"); }`
3. Replace the hash computation: `const hash = `${folder}-${computeContentHash(imageData)}`;` (folder prefix still needed to separate inputs/generations)

WHY: MD5 is already used in save-generation (Phase 13 decision), provides reliable deduplication, and is fast enough for our use case.
  </action>
  <verify>
Build succeeds with `npm run build`. TypeScript types check with no errors.
  </verify>
  <done>
imageStorage.ts uses MD5 hashing, consistent with save-generation API. Same image saved twice gets same hash and is deduplicated.
  </done>
</task>

</tasks>

<verification>
Before declaring phase complete:
- [ ] `npm run build` succeeds without errors
- [ ] `npm test` passes all existing tests
- [ ] No TypeScript errors in modified files
</verification>

<success_criteria>
- Task completed
- All verification checks pass
- Deduplication uses consistent MD5 hashing across all image save paths
</success_criteria>

<output>
After completion, create `.planning/phases/21-fix-image-input-deduplication/21-01-SUMMARY.md`
</output>