Images are one of the most important elements. They can present even more information than words and sometimes stick with readers long after the words have faded away. However, we should be aware of using them wisely.
Large and clear photos take more time to load. Pick pictures that look really good, in PNG format, sized a maximum of 1 MB. Each image should have a purpose behind it. If it doesn’t add value, it’s better not to use it at all.
It's optimal to use your own pictures to show your brand and message the way you want. But if you have to use pictures from somewhere else, make sure other people aren't using the same ones or ones that look almost the same.
When choosing the colors for your email, select your brand’s colors as it increases awareness in the customer's mind. Don’t use too many different colors. Keep it minimalistic and choose up to three colors.
Furthermore, if you put text over an image, make sure to choose text color wisely so it won’t be harder to read.