Shouldn't be a problem. When my brother applied the background in his photo was too dark. and they emailed him asking to send in new photos.
also in my case - they refused my visa because they made a mistake where they thought my job number was not the correct NQF6. i had to just email them (instead of going into a lengthy appeal process), and they reversed the decision with an apology letter to me.
the point is, if you make a mistake, or they make a mistake - do get in touch with them. if it's a genuine mistake they will always try and fix it for you. after all we are all human's and it's in our nature to make mistakes
