Thank you for contacting Syncfusion support.
We have prepared a sample as your requirement which can be downloaded from the following link.
The following thing has been done in the sample.
1. Created a template document Input.docx with replace text” Replace” using Microsoft Word application.
2. Opened the template document and created TextBodyPart instance with WPicture item(by loading an image from folder location) using Essential DocIO.
3. Replace the text” Replace” with WPicture instance.
4. Saved the document.
To know more about these manipulations, kindly refer the following link.
Please let us know if you have any questions.