First read carefully what is written and then go step by step. It will definately upload.
1st Click on the image icon.
Then choose the upload option which is given at the top right corner.
{If you dont get pop up like the image as below then you must enable popup of your browser}
Now after clicking upload you will have choose file option. Then first choose file from your file manager then click on send it to server icon.
Now its uploaded to server now you click on ok button as below.
Now its sure that your image must be uploaded if you follow the same.
After all if it doesn't upload then check that if your browser is allowed to choose images. You can check it by
SETTING - APPLICATIONS - CHROME - PERMISSIONS - STORAGE then then allow it.
