One may see an image for an ad at social media or anywhere, and the image doesn't seem to be related to the caption or title, there is a reason for that. Visual stimulation to trigger curiosity!
Human nature reacts to visual information, hence the adage "a picture is more than a thousand words"! With an effective image, an advert can have little or no words and yet people will take a look and an action (click) because they have now become curious, and that's the goal or marketing.
Don't seek an image to try to match a title that is "How to find the best deals" and show some cartoon icon of a dude with a magnifying glass. That will only stimulate the 8 year old kid who is browsing the web with dad. It must cause the person to pause and take a look, then let the caption define a few reasons why clicking could improve their day.
Ideal image types for visual stimulation
- Cute kids
- Kids doing funny acts
- Lean males
- Men in sport wear
- Men fighting
- Lean women
- Women in lingerie
- Women in swimwear
- Women teasing sexually without being explicit
- Monster graphic (bigfoot)
- Vehicle crash graphic
- Sport cars
- Cash and jewelry (may be played out)
- Anything sexual without being explicit