> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pdf4llm.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Images & Graphics
> Extract embedded images and vector graphics from documents — controlling output path, format, and whether images are written to disk or embedded inline.
## Overview
PDF4LLM can extract images and graphics from documents in two ways: writing them as files to disk, or embedding them as Base64-encoded data URIs directly in the Markdown output. When images are written to disk, their paths are referenced inline using standard Markdown image syntax.
Image extraction is disabled by default. To enable it, pass `writeImages: true` to `ToMarkdown()`.
```csharp theme={null}
using PDF4LLM;
string mdText = PdfExtractor.ToMarkdown("document.pdf", writeImages: true);
```
***
## Writing images to disk
When `writeImages: true` is set, each image found in the document is saved as an individual file. The path to each image is embedded in the Markdown output:
```markdown theme={null}
```
By default, images are written to the process working directory. Use `imagePath` to specify a different output directory:
```csharp theme={null}
string mdText = PdfExtractor.ToMarkdown(
"document.pdf",
writeImages: true,
imagePath: "assets/images/"
);
```
Unlike the Python library, PDF4LLM for .NET does **not** create the output directory automatically. Create it before calling `ToMarkdown()` or you will get a `DirectoryNotFoundException`:
```csharp theme={null}
Directory.CreateDirectory("assets/images/");
```
***
## Image format
Use the `imageFormat` parameter to control the file format of extracted images. Pass the format as a lowercase file extension string:
```csharp theme={null}
string mdText = PdfExtractor.ToMarkdown(
"document.pdf",
writeImages: true,
imagePath: "assets/images/",
imageFormat: "jpg"
);
```
| Format | Best for | Notes |
| -------- | ----------------------------- | ---------------------------------------- |
| `"png"` | Diagrams, screenshots, charts | Lossless. Larger file size. Default. |
| `"jpg"` | Photographs, scanned pages | Lossy. Smaller file size. |
| `"webp"` | Web delivery | Good compression, broad browser support. |
| `"tiff"` | Archival, OCR pre-processing | Lossless. Large file size. |
| `"bmp"` | Maximum compatibility | Uncompressed. Very large file size. |
| `"pnm"` | OCR pre-processing pipelines | Portable bitmap format. |
Use `"png"` when image fidelity matters — for example, when extracting charts, diagrams, or figures that contain readable text. Use `"jpg"` for photographic content where file size is a concern.
***
## Embedded vs. file images
### File images (write to disk)
When using `ToMarkdown()` with `writeImages: true`, images are saved to disk and referenced by path in the Markdown output:
```csharp theme={null}
string mdText = PdfExtractor.ToMarkdown(
"document.pdf",
writeImages: true,
imagePath: "assets/",
imageFormat: "png"
);
```
The Markdown output will contain image references like:
```markdown theme={null}
Some preceding text.
Some following text.
```
### Embedded images (inline Base64)
Set `embedImages: true` to encode images as Base64 data URIs and embed them directly in the Markdown — no files are written to disk:
```csharp theme={null}
string mdText = PdfExtractor.ToMarkdown("document.pdf", embedImages: true);
```
The Markdown output will contain inline data URIs:
```markdown theme={null}
Some preceding text.
Some following text.
```
This produces a fully self-contained output string with no external file dependencies — useful when passing Markdown directly to an LLM or storing it in a vector store.
`writeImages` and `embedImages` are mutually exclusive. If both are set to `true`, `embedImages` takes precedence and no files are written to disk.
***
## Vector graphics
PDF4LLM detects vector drawings — lines, shapes, and filled regions — and includes their bounding boxes in the layout analysis. Vector graphic regions are represented as `"image"` type blocks in `ToJson()` output, giving you their position on the page so you can identify and handle them in your pipeline.
***
## Image file naming
Extracted image files are named automatically using the pattern:
```
{imagePath}/{sourceFilename}-{pageNumber}-{imageIndex}.{imageFormat}
```
For example, the second image on page 3 of `document.pdf`, saved as PNG to `assets/images/`:
```
assets/images/document.pdf-2-2.png
```
Page numbers are zero-based. Image indices are one-based and reset on each new page.
***
## Full example
```csharp theme={null}
using System.IO;
using PDF4LLM;
string imagePath = "output/images/";
Directory.CreateDirectory(imagePath);
// Extract Markdown with images saved to disk
string mdText = PdfExtractor.ToMarkdown(
"report.pdf",
writeImages: true,
imagePath: imagePath,
imageFormat: "png"
);
// Save the Markdown file
File.WriteAllText("output/report.md", mdText, System.Text.Encoding.UTF8);
Console.WriteLine("Done.");
Console.WriteLine($"Images saved to: {imagePath}");
Console.WriteLine("Markdown saved to: output/report.md");
```
***
For the full API signature, see the [ToMarkdown() API reference](/dotnet/api/PdfExtractor#tomarkdown).
***
## Next steps
Full walkthrough of ToMarkdown() with all common options.
Access image bounding boxes via the JSON output.
Table extraction explained.