Wrote some readme and added some feedback functionality. DepthMapNeedle now tells you, when exports are finished and so on.

README.md

@@ -1,2 +1,10 @@
 # DepthMapNeedle
 DepthMapNeedle is a java tool to inject or extract depth information in form of depthmaps from photos shot using Google Cameras Blur function.
+This is a command line tool. Simply extract depth information as a png file by typing 'java -jar DepthMapNeedle -e <Image>.jpg'. The depthmap will be stored in the same location as the image as '<Image>_d.png'.
+In the same way you can extract the unblurred source image by replacing the '-e' with '-s'.
+But the best part is, that you can modify the extracted depthmap in the image manipulation program of your choice and then replace the old depthmap in the image.
+This can be handy in case the original depthmap has some imperfections. Simply extract the depthmap, manipulate it and inject the fixed depthmap back into the image. 
+Now all you have to do is rerender the image in the google camera.
+
+Enjoy ;) 
+Vanitas

src/DepthMapNeedle.java

@@ -10,7 +10,8 @@ public class DepthMapNeedle
 			for(int i=1; i<args.length; i++)
 			{
 				JPEG image = new JPEG(args[i]);
-				image.exportDepthMap();
+				if(image.exportDepthMap()) System.out.println("Depthmap extracted for file " + args[i]+".");
+				else System.err.println("There is no Depthmap in file "+args[i]);
 			}
 		}
 		else if(args.length >=2 && args[0].equals("-s"))
@@ -18,7 +19,8 @@ public class DepthMapNeedle
 			for(int i=1; i<args.length; i++)
 			{
 				JPEG image = new JPEG(args[i]);
-				image.exportSourceImage();
+				if(image.exportSourceImage()) System.out.println("Unblurred source image extracted for file "+args[i]+".");
+				else System.err.println("There is no unblurred source image in file "+args[i]+". Maybe this photo has not been taken with the blur function?");
 			}
 		}
 		else if(args.length >= 3 && args[0].equals("-i"))
@@ -27,7 +29,8 @@ public class DepthMapNeedle
 			for(int i=2; i<args.length; i++)
 			{
 				JPEG image = new JPEG(args[i]);
-				image.injectDepthMap(depthmap);
+				if(image.injectDepthMap(depthmap)) System.out.println("Depthmap injected into file "+args[i]+".");
+				else System.err.println("Something went wrong while injecting "+depthmap+" into "+args[i]+".\nRemember: The first argument has to be a png and the following arguments must be jpgs shot with the blur function.");
 				image.save();
 			}
 		}

src/JPEG.java

@@ -30,32 +30,42 @@ public class JPEG extends Const
 		tail = this.getImageTail();
 	}
 	
-	public void exportDepthMap()
+	public boolean exportDepthMap()
 	{
 		String out = filename;
 		if(out.endsWith(".jpg") || out.endsWith(".JPG")) out = out.substring(0, out.length()-4);
-		this.exportDepthMap(out+"_d.png");
+		return this.exportDepthMap(out+"_d.png");
 	}
 	
-	public void exportDepthMap(String file)
+	public boolean exportDepthMap(String file)
 	{
 		byte[] b64 = ArrayUtils.unsign(extractDepthMap());
 		byte[] depth = Base64.getDecoder().decode(b64);
+		if(depth != null)
+		{
 			IO.write(depth, file);
+			return true;
+		}
+		else return false;
 	}
 	
-	public void exportSourceImage()
+	public boolean exportSourceImage()
 	{
 		String out = filename;
 		if(out.endsWith(".jpg") || out.endsWith(".JPG")) out = out.substring(0, out.length()-4);
-		this.exportSourceImage(out+"_s.jpg");
+		return this.exportSourceImage(out+"_s.jpg");
 	}
 	
-	public void exportSourceImage(String file)
+	public boolean exportSourceImage(String file)
 	{
 		byte[] b64 = ArrayUtils.unsign(extractSourceImage());
 		byte[] src = Base64.getDecoder().decode(b64);
+		if(src != null)
+		{
 			IO.write(src, file);
+			return true;
+		}
+		else return false;
 	}
 
 	public byte[] extractDepthMap()
@@ -139,10 +149,12 @@ public class JPEG extends Const
 		this.disassemble();
 	}
 
-	public void injectDepthMap(String filename)
+	public boolean injectDepthMap(String filename)
 	{
 		byte[] depth = Base64.getEncoder().encode(IO.read(new File(filename)));
 		xmpExt = JPEGUtils.replace(xmpExt, keyGDepthData, depth);
+		if(xmpExt != null) return true;
+		else return false;
 	}
 
 	public byte[] reassemble()