Logos and other brand graphics should be designed using visual ingredients that resonate with your target clientele. Colors, fonts, and imagery should all be chosen carefully, and with consideration for a business' audience.
Functionality of a business' logo in real space begins with the initial design. Attractive artwork does not always result in usable graphics in all applications - such as apparel, engraving, business cards, websites, social media, and more.
Just because logos and images can be found freely online does not mean they belong to a user. Legal conflicts over lack of proper ownership can lead to cease-and-desist letters and lawsuits. Ensure you have full rights to the logo you use.