Magick++ Error when reading BLOB into Image

I'm trying to export an image from raw pixel data into a RGBA PNG using the Magick++ library.

However, I'm getting a strange error when I'm attempting to run it:

terminate called after throwing an instance of 'Magick::ErrorCorruptImage'
  what():  test: unexpected end-of-file `': No such file or directory @ error/rgb.c/ReadRGBImage/229
Aborted

This is the relevant code part (I omitted filling the pixel vector, but that doesn't change anything):

#include <iostream>
#include <vector>
#include <ImageMagick/Magick++.h>

using namespace std;

int main(int argc, char *argv[]) {
    Magick::InitializeMagick(*argv);
    int rres, ires;
    cin >> rres >> ires;
    //RGBA
    //rres: horiz. resolution, ires: vert. resolution
    vector<unsigned char> image(rres * ires * 4);
    Magick::Blob blob(&image[0], rres*ires*4);
    Magick::Image img;
    img.size(to_string(rres) + "x" + to_string(ires));
    img.magick("RGBA");
    img.read(blob);
    img.write("out.png");
}

Compilation with:

g++ --std=c++11 -O0 -g3 -ggdb3 -D_GLIBCXX_DEBUG -Wall test.cpp -o test `Magick++-config --cppflags --cxxflags --ldflags --libs`