Podcasts are an audio medium, yet your website and feed are full of pictures: cover art, guest portraits, behind-the-scenes photos, charts shown in an episode, screenshots from a tutorial. For a blind or low-vision visitor using a screen reader, those images are invisible unless you describe them. Alt text, the short description stored in an image’s alt attribute, is how you do that. It is also what appears when an image fails to load on a weak connection, which makes it useful to far more people than you might expect.

The basic rule: does the image carry information?

Before you write a single word, ask what the image is doing on the page. Every image falls into one of a few groups, and each gets different treatment.

• Informative images add meaning, so they need a description.
• Decorative images add only atmosphere, so they should be hidden from assistive technology.
• Functional images act as buttons or links, so the alt text should say what happens when you use them.
• Complex images such as charts hold a lot of data, so they need a longer explanation nearby.

The right text depends on context. The same photo may need a full description in one article and nothing at all in another.

Decorative images: leave the alt empty

If an image is purely ornamental, such as a swirl behind a heading, a divider line or a stock photo that only fills space, give it an empty alt attribute, written as alt with nothing between the quotation marks. Screen readers then skip it entirely.

The empty attribute is not the same as leaving alt out. With no alt attribute at all, some screen readers read out the file name instead, and you end up with a listener hearing “IMG underscore 4471 dot jpg”. Always include the attribute, even when it is empty.

Cover art and episode artwork

Your show’s cover art is worth describing at least once, ideally on your about page or the top of your site. A good description covers the show name as written on the image and the main visual elements, kept brief. For example: “Cover art for The Garden Hour: a watering can pouring green leaves across a yellow background.”

If the artwork is repeated beside every episode in a list, you do not need to describe it every time. Repeated identical descriptions make listening tedious. Mark the repeated thumbnails as decorative, or use alt text that tells people something different, such as the episode number.

If the artwork contains text, such as the episode title or guest name, that text must also appear in real text on the page. Never let important information live only inside a picture.

Guest photos and people

A guest headshot beside a bio usually does not need a long description. The bio already tells people who the guest is, and the photo adds little they would need. In that case, the guest’s name is enough, or empty alt if the name sits right next to it, which avoids reading the same name twice.

Describe appearance only when it matters to the story. If the photo shows the guest at a research station in the Arctic, or holding the invention you discuss in the episode, say so. Avoid guessing at age, ethnicity or gender. Describe what you can see, or use details the person has shared about themselves.

Charts, diagrams and screenshots

A chart in your show notes often carries the main point of a segment. A short alt text should name the chart and state its takeaway, while the full data goes in text beside it, as a list or table. Something like: “Bar chart of monthly downloads, rising steadily from January to June.” Then the numbers follow in the visible content, so everyone can reach them.

Screenshots work best when the alt text says what the viewer needs to know, not every pixel. If the image shows a settings menu with one option highlighted, mention the menu and the highlighted option. If the screenshot is full of text, copy the important parts into the page itself.

How to write good alt text

1. Start from the purpose. What would a sighted person take away from this image in this spot?
2. Put the most important detail first.
3. Use plain, natural language, as if telling a friend over the phone.
4. Include text that appears on the image.
5. Read it aloud with the surrounding paragraph. It should flow without repeating what the paragraph already says.

Common mistakes

• Starting with “image of” or “picture of”. The screen reader already announces that it is an image.
• Stuffing keywords for search engines. It reads badly and helps nobody.
• Leaving the file name in place.
• Describing a decorative image, which adds noise.
• Skipping alt text entirely on linked images, which leaves a link with no name.
• Putting essential information in an image with no text equivalent.
• Copying the same long description onto every image.

How long should it be?

There is no magic number. Most alt text works well as a single short sentence or phrase, often under about 125 characters, since some screen reader setups handle shorter text more smoothly. Treat that as a guide, not a rule. Cover art may need a little more, a simple icon a lot less. If you find yourself writing a paragraph, move the detail into the visible page text and keep the alt text brief, perhaps pointing to it, such as “Line chart of listener growth, details below”.

Describe the point of the picture, not every pixel of it.

A quick test before you publish

Turn the images off in your browser, or read only the alt text from top to bottom. Does the page still make sense? Would a listener who cannot see the pictures miss anything important? If the answer to the second question is yes, the description needs more work, or the missing information belongs in the main text.

Final thoughts

You do not need to audit thousands of images at once. Start with the ones that matter most: your cover art, any chart or screenshot that carries meaning, and the logos or icons that serve as buttons. Make decorative images empty, make informative ones brief and useful, and build the habit of writing alt text at the moment you upload each new image. A few seconds of thought per picture means your visual work reaches listeners who cannot see it.