Office.Interop.Word: How to add a picture to document without getting compressed

Question

How can I add a picture to a word document without loosing quality using the Microsoft.Office.Interop.Word assembly?

The common way to insert a picture to word document is:

Application wordApp = new Application();
Document wordDoc = wordApp.Documents.Add();
Range docRange = wordDoc.Range();

string imageName = @"c:\temp\win10.jpg";
InlineShape pictureShape = docRange.InlineShapes.AddPicture(imageName);

wordDoc.SaveAs2(@"c:\temp\test.docx");
wordApp.Quit();

This way compresses the picture.

There are optional LinkToFile and SaveWithDocument parameters but the saved image is compressed and a link is not wanted because picture file mustn't exist externally.

For Excel there is the Shapes.AddPicture2 Method with MsoPictureCompress parameter which seems to be for this. But I cannot find any equivalent for Word.

Answer 1

So far I have only found a workaround for this issue:

Application wordApp = new Application();
Document wordDoc = wordApp.Documents.Add();
Range docRange = wordDoc.Range();

string imagePath = @"c:\temp\win10.jpg";

// Create an InlineShape in the InlineShapes collection where the picture should be added later
// It is used to get automatically scaled sizes.
InlineShape autoScaledInlineShape = docRange.InlineShapes.AddPicture(imagePath);
float scaledWidth = autoScaledInlineShape.Width;
float scaledHeight = autoScaledInlineShape.Height;
autoScaledInlineShape.Delete();

// Create a new Shape and fill it with the picture
Shape newShape = wordDoc.Shapes.AddShape(1, 0, 0, scaledWidth, scaledHeight);
newShape.Fill.UserPicture(imagePath);

// Convert the Shape to an InlineShape and optional disable Border
InlineShape finalInlineShape = newShape.ConvertToInlineShape();
finalInlineShape.Line.Visible = Microsoft.Office.Core.MsoTriState.msoFalse;

// Cut the range of the InlineShape to clipboard
finalInlineShape.Range.Cut();

// And paste it to the target Range
docRange.Paste();

wordDoc.SaveAs2(@"c:\temp\test.docx");
wordApp.Quit();

Answer 2

According to Microsoft documentation 2002066 you can add the following DWORD entry...

AutomaticPictureCompressionDefault = 0

...to the following registry keys:

For PowerPoint:

HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\PowerPoint\Options

For Word:

HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Word\Options

For Excel:

HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Options

This still works in Office 2019/Office 365 (You need to change 12.0 to 16.0 then). However, all future documents will not compress any images! This may result in very large file sizes!