Custom Field Display

[djnth]

I'm using the following code to display an image from a user specified URL taken from a custom field in the user profile

<img src="$userinfo[field15]">

It works fine and displays the image if a URL is specified, but if there is no URL it displays a white box with a red "X" through it. I was wondering if there if anyone has some code that I could use in place of the code I'm using that would either display a default image or nothing at all if there is no URL specified.

I'm also using this code

<strong>Website:</strong> <a href="$userinfo[field10]"

to display a clickable link to a website also taken from a custom field. I also need something for this so that it would say "n/a" or "not specified" or even just leave it blank if the user does not specify a link.

Thanks for the assistance!!