GLFW_PLATFORM_ERROR when using glfwSetWindowIcon()

I currently coding a Project using LWJGL 3. Since GLFW 3.2 its possible to add a window icon. I used it like you can see below, but I keep getting the error, and I have no clue why. What am I doing wrong?

What I have tried already:

I have made sure that the file is present in "res/img/icon.png".
The PNGLoader (Found here) works, as I am using textures and it loads them without any problems.

Code:

PNGDecoder dec = null;
try {
    dec = new PNGDecoder(new FileInputStream("res/img/icon.png"));
    int width = dec.getWidth();
    int height = dec.getHeight();
    ByteBuffer buf = BufferUtils.createByteBuffer(width * height * 4);
    dec.decode(buf, width * 4, PNGDecoder.Format.RGBA);
    buf.flip();
    Buffer images = new Buffer(buf);
    GLFW.glfwSetWindowIcon(window, images);
} catch (IOException e) {
    e.printStackTrace();
}

Here's the error that I get:

[LWJGL] GLFW_PLATFORM_ERROR error
    Description : Win32: Failed to create RGBA bitmap
    Stacktrace  :
        org.lwjgl.glfw.GLFW.nglfwSetWindowIcon(GLFW.java:1802)
        org.lwjgl.glfw.GLFW.glfwSetWindowIcon(GLFW.java:1829)
        ch.norelect.emulator.designer.Designer.initialize(Designer.java:81)
        ch.norelect.emulator.designer.Designer.start(Designer.java:48)
        ch.norelect.emulator.Main.main(Main.java:27)

Solution

You are passing the raw pixel data as a GLFWImage.Buffer, but GLFW needs the width and height as well. GLFWImage.Buffer is just a convenience class for putting several GLFWImages next to each other, which each hold properties about an image.

GLFWImage image = GLFWImage.malloc();
image.set(width, height, buf);
GLFWImage.Buffer images = GLFWImage.malloc(1);
images.put(0, image);

glfwSetWindowIcon(window, images);

images.free();
image.free();