How to Change XPS file thumbnails?

1. Extract XPS File to your own temp folder
2. Replace original thumbnail file with new custom
for example in my project :
const string thumbFile = @"\Documents\1\Metadata\Page1_Thumbnail.JPG";

3. Repack all content of temp to new XPS via Zip.


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I'm iranian and my Language is Persian.
Sorry if my English is very Poor!