# PDF Image & Caption Extractor Extract images from PDFs, match nearby captions, and generate an HTML index package using OpenDataLoader > Canonical page: https://elysiatools.com/en/tools/pdf-image-caption-extractor - **Category:** Media - **Keywords:** pdf, image extraction, caption extraction, opendataloader ## Overview Use OpenDataLoader image export and semantic JSON output to build a report of PDF images, nearby captions, and page-level metadata. This is useful for textbooks, reports, presentations, and design documents where figures need to be reviewed or reused. ## Inputs - **PDF File** (file) - **Image Format** (select) - **Pages** (text): e.g. 1,3,5-7 - **Use Struct Tree** (checkbox) ## When to use - When harvesting figures and diagrams from academic papers or textbooks for research databases. - When performing a visual audit of corporate reports to ensure all graphics are correctly labeled and documented. - When migrating content from legacy PDF manuals to digital asset management systems or web-based CMS. ## How it works - Upload a PDF file and optionally specify a page range or preferred image format like PNG or JPEG. - The tool parses the document's internal structure tree to identify embedded image objects and surrounding text blocks. - A semantic matching algorithm associates each image with the most relevant nearby text identified as a caption. - The system packages the extracted images and their metadata into a downloadable HTML index for offline browsing and reuse. ## Use cases - Academic Research: Extracting figures and table descriptions from scientific journals for literature reviews. - Technical Documentation: Collecting screenshots and instructional captions from software manuals for training materials. - Marketing Audits: Reviewing visual branding and associated copy across multiple PDF brochures and catalogs. ## Frequently asked questions ### What image formats are supported for extraction? You can export extracted images in either PNG or JPEG format. ### Can I extract images from specific pages only? Yes, use the Pages field to define specific numbers or ranges such as '1, 3, 5-7'. ### What does the 'Use Struct Tree' option do? It utilizes the PDF's internal logical structure to significantly improve the accuracy of caption matching. ### What is the final output of this tool? The tool generates an HTML file that serves as a visual index of all extracted images and their matched captions. ### Does it work with scanned PDFs? 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