resizing a PImage in Processing 2 and 3

In an Android application that I've written using Processing 2 I have the following:

void setup() {
    if (cam == null) cam = new KetaiCamera(this, camWidth, camHeight, 30);
}

void draw() {
    img = cam.get();
    img.loadPixels();
    img.updatePixels();
    // render the original image to screen, seems to be necessary before resizing...
    image(img, width/2, height/2, height, width);

    img.resize(7, 5);
    img.loadPixels();
    // render the scaled image over the original one
    image(img, width/2, height/2, height, width);
}

This has always worked fine for me while using the Processing 2 Android lib. Now I'm trying to port this to Processing 3. I had to change some details (e.g. width, height have become displayWidth, displayHeight) but what bothers me most is that I'm not able to display the scaled image over the original one. I suspecting it's related to resize() not working quite as expected but I don't know for sure. I am simply not seeing the image though I don't get an error. For testing purposes I checked the color of the first pixel of the resized image - I'm always getting 0, 0, 0 which is certainly not right but doesn't explain why I'm not seeing the image.

Does anyone know what might cause the problem? Have there been any changes between p2 and 3 regarding how resize() works?

Thanks very much, Stefan