The Below Code is used by me to open an image from Storage :
StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
StrictMode.setVmPolicy(builder.build());
File path = new File(Environment.getExternalStorageDirectory() + "/" + "ParentDirectory" + "/" + "ChildDirectory");
File filepath = new File(path + "/" + yourImageName.png);
Uri uri = Uri.fromFile(filepath);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(uri, "image/jpeg");
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Edited Answer :
StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
StrictMode.setVmPolicy(builder.build());
File path = new File(Environment.getExternalStorageDirectory() + "/" + "ParentDirectory" + "/" + "ChildDirectory");
Uri uri = Uri.fromFile(path);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(uri, "image/jpeg");
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);