Boing Boing has an excellent how-to located here on how to opt out of being included in LinkedIn's social media advertising. Briefly, LinkedIn assumes that you consent to LinkedIn's use of your image in the adverstising of its sponsor's products. If you recommend your CPA firm, and your CPA firm purchases advertising on LinkedIn, your photo may appear in that advertising.
This approach may be fine in certain cases. However, besides just the general creepiness of it, employers should be aware that it creates a potential association between your company (not just the individual) and that third party. I can imagine a scenario where a company is suing its former CPA firm and an advertisement appears with the Controller's image in a LinkedIn advertisement for the same CPA firm.
If your company's social media policy allows employees to participate in LinkedIn and other social media sites, consider whether the policy needs an update to require opting-out of this social media advertising.