If you want to use the image for your own purposes, the very least you'll have to do is ask permission. You can also expect to pay something, depending on how you plan to use the image. If you use that image without bothering to ask, you can expect that I will be angry. You can also expect that I will report your usage as abuse. If you use that image to make money, I will sue you. I will also contact your client, explain the situation, and I will sue them as well. The net result will be costs far and beyond what the usage fees would have been.
Q. What about friends and family?
A. What about them? My friends and family know better. They understand that if I email them an image, link to a new image, or give them a framed print, the rights to the image still belong to me. I made the image, it's mine.
Q. Shouldn't you see the use of your image as a compliment?
A. Pound sand. If you want to pay me a compliment, make it in the form of legal tender. I accept PayPal, but not until you sign a formal contract for the intended use of the image.
Q. What if they give you a credit line? Isn't that enough? Surely you will profit from the exposure.
A. Attribution is just fine, as long as it is: Arranged in advance, is accompanied by the agreed-upon payment. I have had images published for more than forty years. Seeing my name next to a photograph is commonplace, and I can manage my own exposure, thank you.
Here's what the PPA has to say about copyright.