ImageUpload component issues

[ranjantanya]

1. Allow overriding the caption on the button (current: "Upload new Picture ")
2. Hide delete button when there is no photo to delete
3. When image size is set to "large", the buttons are too big and not aligned properly
   

[rushi]

1. Done in X2-6577 commit.
2. I think we can handle that from the source library for now.