C++ OpenCV imread not working in Android

I am trying to read an image in my C++ code

LOGD("Loading image '%s' ...\n", (*inFile).c_str());;
Mat img = imread(*inFile, CV_LOAD_IMAGE_GRAYSCALE);
CV_Assert(img.data != 0);

and get the following output:

09-25 17:08:24.798: D/IRISREC(12120): Loading image '/data/data/com.example.irisrec/files/input/osoba1.jpg' ...
09-25 17:08:24.798: E/cv::error()(12120): OpenCV Error: Assertion failed (img.data != 0) in int wahet_main(int, char**), file jni/wahet.cpp, line 4208

The file exists. But strange is, that if I try to preview the image using Root File Browser it is just black. I copied the files there manually.

EDIT:

The code works fine under Windows with .png and .jpg format. I am just trying to port an existing C++ project for Iris Recognition to Android.

Solution

I was able to solve this issue only by copying the image files in code.I stored them in my asset folder first and copied them to internal storage following this example. If someone can explain this to me please do this.