Small-business owners have long known that word-of-mouth is their single biggest and often most beneficial form of marketing. According to a recent hyperlocal business survey conducted on Toluna, friend and colleague recommendations topped the list of sources for referrals for local businesses (accounting for 43 percent of them).

With social media, word-of-mouth has taken on a whole new life as it can be tracked, measured and amplified.

Businesses understand that consumer reviews are integral to online shopping, but as social and mobile have evolved, the way opinion and experiences are shared have become multidimensional. Word-of-mouth is no longer just about words. Photos are an integral part of the social media experience and have raised the stakes for how the word-of-mouth spreads.

Related: Twitter Is Going All In On Photos. Here's How.

Sites like TripAdvisor have for a while embraced photo sharing to deliver a real-world view of hotels, sourced by the crowds of visitors. Yelp has increasingly become a site for consumers to share everything from menus and food presentation to the ambiance of any reasonably popular business. Facebook posts with photos have a higher level of engagement than posts without them, while tweets with photos can experience a fivefold engagement increase over text-only tweets.

And then there's Instagram, which silently sneaked up on small businesses to offer a new channel for local word-of-mouth marketing. My company Closely recently analyzed the social activity of 20,000 businesses on our Perch platform with an active Facebook or Instagram presence. While the number of posts on Facebook and Instagram were about the same, the Instagram images generated 40 percent more “likes” and 10 percent more comments than the Facebook posts did.

Small business owners can consider the following insights about using photos as a means of word-of-mouth.

Related: Lessons From Top Brands on How to Rock on Instagram

Photos often capture customers' best experiences. Browse Instagram and you'll notice how much it has become a place to share positive things. The vast majority of Instagram photos posted at businesses locations are of customers having great experiences. Photos of a poor experience or product are generally shared elsewhere, like on TripAdvisor.

Friends follow photos. Instagram has become the go-to place for people to follow their friends, for an experiencing that's like their own network sort. That means a posted photo is enjoyed directly and predictably by friends of the photo's source. As such, influencing a single friend in that network is a way of influencing them all. Typically the person sharing the most photos is the key tastemaker in the bunch and the one a business most wants to reach.

Photos are participatory. When a customer posts a photo, the small business owner has an opportunity to become part of the conversation by liking or commenting on positive and popular experiences. It’s a simple and powerful tactic that more business owners should use.

Think of this as a virtual version of a manager coming over to a table and thanking a customer for his or her business. Everyone likes it, and it helps reinforce a quality experience. And in the social space, that photo becomes an amplifier of the word-of-mouth!

To capitalize on the potential of photos for a company's marketing strategy, here are four easy tips to get started:

Related: Meet the Algorithm That Can Predict Your Photo's Popularity Before You Post It

1. Monitor photos about the company on social media. Create hashtags on Instagram, Twitter and other platforms and encourage patrons to use them when posting photos about the business so allow for better tracking of what’s being shared. Also look into monitoring solutions like Perch to see what people are saying about the company outside of its accounts or hashtags.

2. Encourage photo sharing about the business. Is a business location “Instagram-friendly”? Think about ways to create a great environment in which customers can create a fun-experience selfie. Put the company's Instagram address on the menu or on the retail counter. Let customers know that sharing their experiences is welcome!

3. Join in the share party. Once a company has a handle on what people are posting about its business, staffers should like a customer's photo and comment with a simple word of thanks. It could be shared with the company's followers as well. Consumers are sharing and posting in ways that can be repurposed by businesses seeking to amplify the word-of-mouth these photos represent.

4. Create photos, even sponsor contests. Make the best use of social media by posting the company's own images. Control the way the product looks and let customers add their thoughts and experiences to product pictures. Encourage others to take the  types of photos most desired by hosting contests that require taking and sharing a photo to participate. 

Related: This Crucial Market Research Can Help Your Company Shine