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When readers meet your post, they have two key elements for deciding whether they want to invest their time in your words. Title and picture. One of the two has the most direct impact. Guess which one.
If you want to stand out among other posts, you definitely want to pick your featured picture with care.
Before reading your story, they have to decide to read it. Help them.
Emotions
We all know that emotions are usually the engine of decisions. Or they give a big boost.
What is your title hinting at? Solving a problem? Giving an answer? Sharing an experience?
Which are the emotions connected to the value you want to share? Which are the emotions expected after reading the article?
Well, the more your picture raises emotions in sync with the message of your article the more you will attract readers interested in your article. It’s not about baiting. It’s about inviting interested readers.
A picture which doesn’t raise emotions, or which raises the wrong emotions, falls flat, at best, or is a big sign of no entry.
If you have options between negative emotions and positive emotions, stay on the positive side, of course, but don’t be afraid to show negative emotions, when appropriate and respectful.

Respect
While trying to attract readers, it’s easy to cross the line, even without noticing.
Beyond emotions there are people. Respecting both the readers and the non-readers shows that you care. You don’t want to be here for the day. You want the long run.
Put yourself in different shoes.
Getting extra readers – for the single post – by offending or annoying is not just bad; it’s not worth. You have to promote and enhance your message, not give your image a useless ballast.
Representativeness
The picture should be someway related to the article. Plain common sense.
The picture carries a promise too, as the title does. A promise about the subject or the expected outcome. Picking a picture that is not representative of your story will attract readers with the wrong expectations. Don’t use your title as an alibi – “The title was clear!” – . You know that they will choose also based on the picture. If you keep the promise of your title but not of your picture, you’ll have kept only half of the promises.

Class
Picking the obvious will tell something about your writing. Some stock photos may tell that your writing is boring and obvious. You should be original, while avoiding insignificant, coarse, mean, and unnecessarily provocative choices.
Don’t rush your search. Look at your story from different angles. You’ve written about writing? Don’t search for writing. Blogs are full of typewriters already. What are you saying about writing? That it’s hard? That it helps thinking? Extract the angle. Connect it with emotions. Search difficult. Search win. Search thoughtful.
Then, don’t pick the first picture. Take your time. Scroll. Search for the original, the classy, the amusing, maybe even in humorous contrast with the content. But don’t exaggerate and don’t mislead.

Don’t distract the reader
If you want sadness, search for the most essential picture about sadness. One face. One silhouette. One gesture. One goodbye. Anything else is not richness. It’s a distraction. It’s a dilution of the impact.
Complex scenarios may confuse the reader. House, trees, and a lake. What does that mean? Holiday? Travels? Serenity? Retirement? It may be obvious from the title, but you already have lost your impact opportunity.
More elements combined may also convey a message as a whole, of course. But be sure that the many elements are adding significance, not confusion.

Make picture and title work together
Some pictures may convey more than one message. You may discard them because of their complex meaning, but remember that they are placed near your title. Once your title and your image are coupled, the meaning may become very clear.
Or you want to give nuance to your title or to enrich it. The picture is not required to work isolated and to bring on its shoulders the whole introduction. On the contrary, you may miss opportunities, by focusing on the image only. The picture will introduce your story together with the title.

The quality
Bad pictures, regarding resolution, light, composition, and so on, tell either that you were in a rush or that you have a bad taste. Readers will understand that you don’t care enough and that you settle on mediocrity.
Of course, if you have hi-res photos you have to reduce them – you need quality, not the best possible resolution -, or the image will load slowly with some connections. You may also want to do some editing – maybe to enhance sharpness, or colors, or contrast – or to crop a portion. It’s not a photo class, but it’s an introduction to your post, and it will be seen on smartphones more than you’d wish.
Clear chromatic choices
You won’t print a wall-size poster, contemplated calmly. It will be a few inches at best, on display, glanced.
Your picture has to introduce itself immediately – be it in color or black&white – maybe in a very small size.
Elements must immediately be recognizable. A leaf with a certain shade of green on a background with another shade of green is a bad choice. Maybe wonderful, but it’s not for a post. The chromatic identity of each element and the chromatic personality of the whole picture is usually essential to the impact.

The brand
How you pick the pictures tells something about you. Obvious pictures tell that you hurried up, that you don’t care about details. It may even tell that you care about your audience only up to a point.
You should always be careful, in selecting your pictures, and set certain requirements in line with your identity as an author. There’s no need to appear what you are not, or to be controversial outside the goals of your writing or your business.
You may also choose your pictures around an underlying theme, connected to a major aspect of your brand.
Or you can narrow the options in different ways. For example, only elegant pictures, or only persons, or only a dominant color. This will make much more difficult to pick the best photo, and it’s not a choice for every blog or author, but you gain a visual identity. Your posts will be visually recognizable.
Where
You can easily find stock pictures on the Web, with free access and license.
Here are my preferred three:
- Pexels. Small quantity but good quality. My first choice.
- Unsplash. Large store. You’ll surely find something here. Many obvious photos but also many good ones.
- DeviantArt. This is my weird source, when I want an original touch. It may be too original and weird for someone, and you have to rummage, but you can find pearls.
Photos from Pexels and Unsplash can be freely used and modified. No attribution required, even if it’s appreciated (of course, I recommend it). On DeviantArt there’s no standard license so, unless specified for the single photo or author, you should contact the author for authorization.
You can also google, of course. Results are usually poor or unusable, but you have the opportunity to refine your search much more than on the stock websites. I use it sometimes, when I don’t find a good match on my preferred sites.
Now… Happy picking!
And remember that advice sometimes works better when you don’t follow it.