Social media advertising and especially text-based online platforms have been studied for decades. Still, the investigation of the most effective mix of key design elements in Instagram ads in relation to consumer purchase intention and brand image is still underexplored. This study aims to examine the impact of three key advertisement design elements (colour, font size and layout) on brand image and consumer purchase intention. Three hundred twenty participants were randomly assigned to the conditions of the experiment. The findings provided insights into the way the design elements alter the intention of the consumers to buy and their perceptions of the brand image respectively.