They do convey something very important: credibility.<p>Or, at least, they coerce the fast pace internet viewer into having that first impression.
I know its silly, but the average viewers mind will subconsciously attribute more effort and quality - thus, credibility - to a polished photo than to any gradient.<p>It sadly does not make a difference if its merely a stock photo bought for a few bucks. It still works.<p>Also, a photo gives a more &quot;real&quot;, less abstract impression, so the target customer can relate. You can&#x27;t relate to a gradient.
So the photo should be chosen according to the target customer.<p>I agree though that some effort should also be put into technical aspects, e.g. making the photo file size as small as possible.