Re: Age and Gender
This article shows you to calculate the age:
http://code.hyperspatial.com/all-code/buddypress-code/buddypress-age/
If you want to display the gender as an image, you can do it with a simple PHP if clause that checks your gender field and inserts the correct tag appropriately (or marks the field up with a class identifier), and style as a background image in your CSS.
I suggest posting your “check for online” query as a separate forum post, so that it doesn’t get overlooked
