Q:

How to send JSON file multiple images to the server in android?

[{"Id": 878,
"familyList": [{
        "photocopy": "\/storage\/sdcard\/jsonFiles\/captured_signs\/Signature_1582782604563.jpg",
        "signature": "\/storage\/sdcard\/jsonFiles\/captured_signs\/Signature_1582782604563.jpg"
    }]
}, 
{
  "Id": 877,
  "familyList": [{
        "photocopy": "\/storage\/sdcard\/jsonFiles\/captured_signs\/Signature_1582802338008.jpg",
        "signature": "\/storage\/sdcard\/jsonFiles\/captured_signs\/Signature_1582802338008.jpg"
    }]
}]

A:

You can't store Images at a JSON file. You'll need to access the image that is currently in your Android device before you connect with the server, and parse the Image to Base64 to pass the image Bytes to the server.
Something like this... 
Bitmap bm = BitmapFactory.decodeFile("/path/to/image.jpg");
ByteArrayOutputStream baos = new ByteArrayOutputStream();  
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object   
byte[] b = baos.toByteArray(); 

