> ## 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 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)