Default Profile Photo

I would like to have a default profile photo when the user has not add a photo.

For Female, Male and couple i would like to have a separated photo

With the default photos for a male or a female, just replace already existing pics with your pics (same size of course) and must be same format..ie...(jpg..gif) unless you can find the code to change the gif to jpg like I am searching for. As for couples, sorry no clue there, not gotten to that section yet on my site.

Thank you for your answer.
Every user has got his own (profile)photo galley, but when the personal photo galley is empty i would like to show automatically a default photo.
I've looked for many times in administration, and i don 't know how to mod the php it's pretty complex for me as a new be.