No more try catch around getValue

CHANGELOG.md

 ### unreleased (master branch)
 
+-	Breaking : The image module no longer swallows error thrown by `options.getImage` and `options.getSize`. It is the implementors responsibility to not throw any errors, or the error will be passed. You can return a falsy value in getImage to not render an image at all.
+
 ### 3.0.2
 
 -	Fix issue with PPTX : Before, you had to add to your options : {fileType: "pptx"} in the module options passed as argument in the constructor of the module. Now, the fileType is retrieved from the main docxtemplater.

es6/index.js

@@ -91,20 +91,18 @@ class ImageModule {
 		if (!part.type === "placeholder" || part.module !== moduleName) {
 			return null;
 		}
-		try {
 		const tagValue = options.scopeManager.getValue(part.value);
 		if (!tagValue) {
-				throw new Error("tagValue is empty");
+			return {value: this.fileTypeConfig.tagTextXml};
 		}
 		const imgBuffer = this.options.getImage(tagValue, part.value);
+		if (!imgBuffer) {
+			return {value: this.fileTypeConfig.tagTextXml};
+		}
 		const rId = imgManager.addImageRels(this.getNextImageName(), imgBuffer);
 		const sizePixel = this.options.getSize(imgBuffer, tagValue, part.value);
 		return this.getRenderedPart(part, rId, sizePixel);
 	}
-		catch (e) {
-			return {value: this.fileTypeConfig.tagTextXml};
-		}
-	}
 	getRenderedPart(part, rId, sizePixel) {
 		if (isNaN(rId)) {
 			throw new Error("rId is NaN, aborting");