Search engines have index content for image alt and title attributes. In other words, this means if you have images that you also explain on the page you may get a better ranking for this. There are those with visual disabilities that need the images explained to make sure they are looking at the right product. In this area you can increase your ranking by having a short description with keywords. You don’t want to keyword stuff of course.
Be descriptive in the material as well as concise. Make it easy for the visually impaired to get what they need. They may be using a screen reader to help magnify items and this means you need to describe the images as they may not be clear. One or more targeted keywords is important to the overall plan.
If the image is a link this is also very important. You want to provide the anchor text for the image in the link. This is essential to the search rankings you are trying to obtain. The image should be HTML as well as the text. You don’t really have to put bullet points or spacers in the tags, but it is helpful. This of course doesn’t have much to do with ranking.