What is a picture worth? We have all heard the expression, but is it really that simple?

The world has gone mobile. With thousands of smartphones and connected devices, people expect to find what they are looking for in a matter of seconds ? and they usually do. 

Whether it is the latest viral video, instant entertainment, a helpful article on harvesting tomatoes, or the perfect pair of shoes to match a new outfit, it is critically important to get the right information in front of the right person at the right time ? usually in fewer than 140 characters.

So when your content is up against thousands of others fighting for the attention of a single person, how can you best grab it and hold onto it? 

Small screens and short attention spans demand effective marketing. 

The average consumer attention span is only eight seconds. So not only do you need to get their attention in the first place, you need to keep it and tell them everything they need to know in eight seconds or less.

Think about your personal habits. 

When you are scrolling through the day?s news ? whether you are on Facebook, Twitter, your favorite news source, or even search results ? where are your eyes drawn? 

If two of 10 stories feature a prominent image, I would bet good money that your eyes go to one of those two first.

In the fast-paced world of consumer attention, people do not take the time to stop and read. They need to absorb your message as if through osmosis, extending as little effort as possible. 

When every millisecond counts, you need to think critically about the effectiveness of the message you are sending.

Not only are pictures effective ? necessary, even ? to grab attention towards your ad or post, they also help viewers retain your message. 

People only retain about 10 to 20 percent of the information they read. How much can you say in 10 percent of one tweet? That is probably only three words.

Add an image to that same tweet, and now your viewer will remember close to 30 percent of the text with it. And if you choose the right image ? one that reinforces and conveys your marketing message succinctly ? you can direct their attention and spark their memory. 

Whether it is a headline or branding message or call-to-action, the combination of an impactful image and the right message is the must-have formula for effective marketing. Images are not just a good idea, they are critical.

But where does it end? Where is this trend heading next?

Pictures soon may not be good enough. 

As pictures fill news feeds, Web sites and search results, an image alone is not enough to hold their focus. You need more. You need video. 

Whether it is a how-to, a new product showcase, a behind-the-scenes peak, or an in-depth interview, video is a great way to tell your story and grab the attention of your viewers on social media. 

Video helps customers remember more of your message. When you use both visuals and audio, your customers can see and hear your message and will remember about 70 percent, a dramatic improvement over the 10 percent with text alone.

But video is facing many of the same challenges as photos and text on social media, namely the shrinking attention span of customers. 

The things you used to be able to share in a two-minute video you now have to squeeze into a 15-second video. Running an ad on YouTube? You have less than five seconds to grab and hold the viewer?s attention before she can ? and will ? choose to skip your ad.

The caveat here is that simply having a picture, image or video is not enough. 

If you are lucky, the presence alone may be enough to pull their focus for a brief, fleeting moment. But if you want to keep their attention? You need to earn it.

Jerry Seinfeld shared this insight: ?There is no such thing as an attention span. There is only the quality of what you are viewing.? 

Long-form content is not extinct, it is just taking a more specialized role in the world of mobile and digital marketing. 

But what has always rung true for longer content is now true of all content: you have to earn your customer?s attention. 

Simply adding a picture or video is a ruse, and mobile viewers will see through it quickly. But adding value to reinforce your content builds trust and beckons the viewer in for a closer look.

Ultimately, once you have earned their trust and authority, they will hang on every word you have to say, whether it is a 140-character tweet or a 20-page ebook. 

Only when you build true value into the content will you find success.