image retrieval
**Image retrieval** is the **retrieval process that finds relevant images from a corpus using visual similarity, text queries, or both** - it is important when key evidence is encoded in figures, schematics, and photos.
**What Is Image retrieval?**
- **Definition**: Search and ranking over image assets using embeddings, tags, and metadata.
- **Query Modes**: Supports text-to-image retrieval, image-to-image similarity, and hybrid search.
- **Index Signals**: Uses visual embeddings, OCR text, captions, and source metadata.
- **RAG Role**: Provides visual evidence that can be summarized or cited in final answers.
**Why Image retrieval Matters**
- **Visual Evidence**: Many troubleshooting clues appear only in photos or interface screenshots.
- **Context Enrichment**: Images can clarify procedural steps better than text alone.
- **Recall Gains**: Image channel recovers facts missed by sparse textual descriptions.
- **Domain Utility**: Engineering and manufacturing workflows rely heavily on diagram interpretation.
- **Trust Improvement**: Showing matched visuals increases answer verifiability.
**How It Is Used in Practice**
- **Embedding Pipeline**: Generate image vectors and store links to original assets and captions.
- **OCR and Captioning**: Extract text overlays and semantic descriptions for hybrid indexing.
- **Result Grounding**: Attach top visual matches to generated responses with provenance metadata.
Image retrieval is **a critical retrieval capability for visually grounded AI systems** - effective image indexing and ranking expands evidence coverage and response quality.