Update profile picture in SharePoint Online by using SharePoint hosted app, via JavaScript or jQuery

 <input id="uploadInput" type="file" />

 var fileInput = $('#uploadInput');

        for (var i = 0; i < fileInput[0].files.length; i++) {
            var file = fileInput[0].files[i];
            processprofilepic(file, '');
        }

        function processprofilepic(fileInput) {
            var reader = new FileReader();
            reader.onload = function (result) {
                var fileName = '',
                 libraryName = '',
                 fileData = '';

                var byteArray = new Uint8Array(result.target.result)
                for (var i = 0; i < byteArray.byteLength; i++) {
                    fileData += String.fromCharCode(byteArray[i])
                }

                // once we have the file perform the actual upload
                console.log("filename "+fileName);
                setprofilepic(fileData);

            };
            reader.readAsArrayBuffer(fileInput);
        }


        function setprofilepic(fileData) {


            url = shptService.appWebUrl + "/_api/SP.UserProfiles.PeopleManager/SetMyProfilePicture";


            // use the request executor (cross domain library) to perform the upload
            var reqExecutor = new SP.RequestExecutor(shptService.appWebUrl);
            reqExecutor.executeAsync({
                url: url,
                method: "POST",
                headers: {
                    "Accept": "application/json; odata=verbose",
                    "X-RequestDigest": fDigest
                },
                contentType: "application/json;odata=verbose",
                binaryStringRequestBody: true,
                body: fileData,
                success: function (x, y, z) {
                    alert("Success! Your file was uploaded to SharePoint.");
                },
                error: function (x, y, z) {
                    alert("Oooooops... it looks like something went wrong uploading your file.");
                }
            });
        }