Yes, technically a photo can be used as part of a logo, but there are several things to consider.
Photos, while looking great on our monitors or even printed, will completely lose their meaning when shrunk to fit on a business card and will pixelate if blown up to be used on a banner.
Logos should be versatile, meaning they should look good in any medium, whether printed, on a website, on merchandise, or in black and white or color. Photos may not have the same impact or readability in all these scenarios.
If a photographic element is crucial for your branding, you might consider stylising it into a simpler, more graphic form or using it as part of a larger branding scheme rather than the logo itself.
Kimberley Web Design encourages clients to use a Vector Graphic.