> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ImageSourceTypeEnum

> ImageSourceTypeEnum in the ABBYY FineReader Engine API — Possible input image sources (scan, photo, etc.) used to choose preprocessing techniques.

ImageSourceTypeEnum enumeration constants are used to define possible sources for input images. This helps determine whether to use special preprocessing techniques.

```
typedef enum {
 IST_Auto,
 IST_Photo,
 IST_Scan,
 IST_Screenshot,
 IST_SyntheticImage,
 IST_SyntheticText
} ImageSourceTypeEnum;
```

## Elements

| Name                  | Description                                                                                                                   |
| --------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| IST\\\_Auto           | Detect the image origin automatically.                                                                                        |
| IST\\\_Photo          | The image is a photo.                                                                                                         |
| IST\\\_Scan           | The image is a scan.                                                                                                          |
| IST\\\_Screenshot     | The image is a screenshot.                                                                                                    |
| IST\\\_SyntheticImage | The image contains text that is obtained by rasterizing digital fonts. For example, a digitally-born image-only PDF document. |
| IST\\\_SyntheticText  | The image contains a text layer. For example, a digitally-born PDF document with a text layer.                                |

## Used in

[IPrepareImageMode::ImageSourceType](/fine-reader/engine/api-reference/image-related-objects/prepareimagemode#imagesourcetype)