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      How to: Save Selected Image to a File
      How to: Reduce the File Size When Saving a Document Containing Pictures
      How to: Retain the Image URI in HTML Document
      How To: Export Document to PDF format
      How To: Export Document to HTML format
      How to: Determine Formatting Capabilities Required to Export the Document
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View this topic on docs.devexpress.com (Learn more)

How to: Retain the Image URI in HTML Document

This example describes HTML export in more detail and provides a solution on how to store the original image URI in the exported document.

When RichEditControl loads an HTML document, it performs HTML import and transforms the document into a native document model. When RichEditControl saves a document, it performs a document export from the native format to the resulting document's format.

When saving a document as HTML, there are two options for saving images, described in the table.


HTML Sample

Embed images into the resulting file as base64-encoded data

Save images as separate files. The images are named with the "image" word followed by its sequential number in a file. Images are saved to the folder with the name that is the combination of the file name, underscore and the "files" word. That is, the first png image in the resulting Test.html file is saved to the Test_files\image0.png location.

Different methods produce different results, as shown in the following table.

Export Result
RichEditControl.HtmlText property Images are contained in the resulting file as base64-encoded data.
SubDocument.GetHtmlText method The HtmlDocumentExporterOptions parameter allows specifying embedded or standalone images by setting the HtmlExportOptionsBase.EmbedImagesInHTML property.
RichEditControl.SaveDocument or RichEditControl.SaveDocumentAs methods, the SaveDocumentAsCommand command The HtmlDocumentExporterOptions.EmbedImages property accessible using the RichEditControl.ExportOptions.HtmlOptions.EmbedImages notation determines whether images are embedded or saved as separate files.

The HTML exporter uses an URI provider instance to obtain the URI string for each image. There are several built-in URI providers - the FileBasedUriProvider which provides image file names and the DataStringUriProvider that constructs a tag for embedded base64 data. The built-in URI provider service (a service that implements the IUriProviderService interface) is used to obtain a provider instance of a proper type.

You can implement a custom URI provider to specify a custom location for each image when the document is saved to an HTML format. To accomplish this, create a IUriProvider descendant and register it in RichEditControl services.


The SubDocument.GetHtmlText method allows you to specify a custom URI provider as the method's parameter, bypassing the URI provider service and the RichEditControl.ExportOptions.HtmlOptions.EmbedImages option.

Each image in RichEditControl has the OfficeImage.Uri property that is the original image URI. To save an original image URI to the exported HTML document, our custom UriProvider returns the OfficeImage.Uri value.

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