paragraphinsertInlinePictureFromBase64.js

// Run a batch operation against the Word object model.
Word.run(function (context) {
    
    // Create a proxy object for the paragraphs collection.
    var paragraphs = context.document.body.paragraphs;
    
    // Queue a commmand to load the style property for all of the paragraphs.
    context.load(paragraphs, 'style');
    
    // Synchronize the document state by executing the queued-up commands, 
    // and return a promise to indicate task completion.
    return context.sync().then(function () {
        
        // Queue a command to get the first paragraph.
        var paragraph = paragraphs.items[0];

        var b64encodedImg = "iVBORw0KGgoAAAANSUhEUgAAAB4AAAANCAIAAAAxEEnAAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAACFSURBVDhPtY1BEoQwDMP6/0+XgIMTBAeYoTqso9Rkx1zG+tNj1H94jgGzeNSjteO5vtQQuG2seO0av8LzGbe3anzRoJ4ybm/VeKEerAEbAUpW4aWQCmrGFWykRzGBCnYy2ha3oAIq2MloW9yCCqhgJ6NtcQsqoIKdjLbFLaiACnYyf2fODbrjZcXfr2F4AAAAAElFTkSuQmCC";

        // Queue a command to insert a base64 encoded image at the beginning of the first paragraph.
        paragraph.insertInlinePictureFromBase64(b64encodedImg, Word.InsertLocation.start);
        
        // Synchronize the document state by executing the queued-up commands, 
        // and return a promise to indicate task completion.
        return context.sync().then(function () {
            console.log('Added an image to the first paragraph.');
        });      
    });  
})
.catch(function (error) {
    console.log('Error: ' + JSON.stringify(error));
    if (error instanceof OfficeExtension.Error) {
        console.log('Debug info: ' + JSON.stringify(error.debugInfo));
    }
});