能否不使用关系将图片直接嵌入OOXML内容中？

Yes, it is possible to embed image content directly in OOXML files using base64 encoding, though this is not the standard or recommended approach for most use cases. Here's how it works, along with key considerations and alternatives:

How to Embed Images Directly #

There are two primary ways to embed image data inline in an OOXML package:

1. Data URI in Relationship Target #

Instead of pointing a relationship to a file in word/media, you can set the relationship's Target attribute to a base64-encoded data URI.

First, add a relationship entry in the relevant .rels file (e.g., word/_rels/document.xml.rels):

<Relationship 
  Id="rId1" 
  Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" 
  Target="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH5gMVESkqQzkWtAAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeBDhcAAAAUSURBVDjLY2AAAUaG4UYxDDgAAAC8AAH0bHcgAAAAASUVORK5CYII=" 
/>

Then reference this relationship in your document's XML as usual:

<w:drawing>
  <!-- ... other tags ... -->
  <pic:blipFill>
    <a:blip r:embed="rId1" cstate="none"/>
    <!-- ... other tags ... -->
  </pic:blipFill>
  <!-- ... other tags ... -->
</w:drawing>

2. Inline Binary Data in Relationships #

You can also embed the raw base64 data directly within the relationship element using pkg:binaryData (requires setting TargetMode="Internal"):

<Relationship 
  Id="rId1" 
  Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" 
  TargetMode="Internal"
>
  <pkg:binaryData>iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH5gMVESkqQzkWtAAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeBDhcAAAAUSURBVDjLY2AAAUaG4UYxDDgAAAC8AAH0bHcgAAAAASUVORK5CYII=</pkg:binaryData>
</Relationship>

Key Considerations #

• Compatibility: Modern versions of Microsoft Word and most OOXML-compliant tools support inline base64 images, but older software may have issues parsing large base64 strings.
• Performance: Base64 encoding adds ~33% overhead to the image size, which can bloat XML files and slow down parsing, especially with large or numerous images.
• Maintainability: Inline base64 data makes XML files harder to read, edit, and debug compared to referencing separate media files.

Recommended Approach & Alternatives #

• Standard Reference Method: The default approach (storing images in word/media and referencing via relationships) is preferred for its efficiency, readability, and broad compatibility.
• SVG Images: If your image is SVG-based, you can embed the entire SVG XML content directly in the w:drawing element without base64 encoding. This avoids overhead and keeps the content human-readable.
• Single-File Distribution: If you need a single file for sharing, note that .docx files are already ZIP archives containing all assets—you don’t need to embed images inline to have a single distributable file.

内容的提问来源于stack exchange，提问作者gmn_1450