How do I describe a sequence of images without repeating the same setup?

Separate the shared context from the image-by-image details. Write one short introduction that tells readers what connects the images, then give each image its own description of what is visible or distinctive in it. The W3C Web Accessibility Initiative distinguishes a collection of related images from images that together convey one piece of information. For a collection, it recommends individual alternative text and a description of the images’ relationship; its example introduces a shared context before describing each image separately. [S1]

A practical outline is:

1. Shared introduction: What links the images, if that is clear from the material?
2. Image descriptions: What does each image show that readers need to know?
3. Relationship or order: Are they labeled, sequenced, or otherwise connected? State only what the material supports.

The shared introduction should not replace each image’s individual description. Nor does the guidance establish a general prose formula for every kind of sequence; adapt the wording to the images and their purpose.

Use the introduction for the common frame: the subject, collection, or stated purpose shared by the images. Keep it brief enough that readers do not have to read the same scene-setting sentence repeatedly. Use each individual description for details that distinguish that image and matter to understanding it.

For example, the introduction might identify a set as “Three views of the same garden.” Individual descriptions could then name the visible viewpoint or feature in each view. But only use “same garden” if the material identifies or clearly supports that connection. If all you know is that the images are displayed together, say something more cautious, such as “A collection of three garden images.” Do not infer that they show the same place, different seasons, or a progression unless that information is provided or visible.

Here is a fictional example, assuming the supplied images are three labeled drawings of a paper airplane, and that the labels and visible details match the descriptions. It is an example of structure, not a claim about real images:

Introduction: “A three-image collection of paper-airplane drawings.”

Image 1: “A paper airplane is drawn above a horizontal line.”

Image 2: “A paper airplane is drawn below the line, with its nose pointing left.”

Image 3: “A paper airplane is drawn beside a dotted line.”

This example names visible differences without asserting that the airplane moved, flew, or changed over time. If the images are explicitly numbered and intended to show steps, you can mention that stated relationship in the introduction. If not, describe the collection without presenting it as a sequence of events. Before using any detail, check it against the actual image.

Call them a sequence when the supplied material supports an order or progression—for example, through numbering, an accompanying explanation, or an evident step-by-step arrangement. Otherwise, “related images” or “a collection” may be more accurate. A visible difference does not by itself prove that one image comes before another or that an event caused the difference.

When the relationship is unclear, describe each image plainly and flag the uncertainty for whoever supplied or approved the material. You can ask: “Are these images meant to be read in a particular order?” or “What shared context should readers know?” Until you have an answer, avoid adding an unverified setting, timeline, or explanation. The final descriptions should let readers distinguish the images without making them carry a story the images do not establish.