Image SEO for Shopify Stores: Alt Text, Files and Theme Code

Who it is for

Any Shopify store with product photos

Time needed

An afternoon for your top products

What you need

Admin access, and theme code access for the checks

Every image on a Shopify store passes through three hands before a shopper sees it: yours when you upload it, Shopify's CDN when it resizes and converts it, and your theme's Liquid code when it writes the HTML. Image SEO is getting all three right. Shopify does most of the CDN work well by default, so the gains are almost always in what you upload and how the theme outputs it.

This guide covers what Shopify does with images out of the box, how to prepare files, where to add alt text for every kind of image in the admin, what to check in theme code, and the mistakes I see most. Shopify limits and Google guidance are as I checked them on 7 November 2026.

What Shopify does with your images by default

It helps to know what's already handled, so you don't pay for an app to do it twice.

Image compression apps were essential years ago. Today the CDN already serves a modern format at the size the browser asks for, so the original file's weight matters far less than it used to. What still matters is starting with a sharp image at a sensible size, and a theme that requests the right width.

Step 1: Prepare files before you upload

1. Pick the format. Shopify recommends PNG for most product images, followed by JPEG. It also accepts WebP, GIF, HEIC, TIFF, BMP and SVG. The CDN converts for the shopper's browser either way.
2. Size it. Shopify accepts images up to 5000 x 5000 px or 25 megapixels, under 20 MB. For square product images, 2048 x 2048 px usually displays best and leaves room for zoom.
3. Keep one aspect ratio per catalog. Mixed ratios make collection grids uneven and can cause layout jumps. Choose square or portrait and stick to it.
4. Name the file. Google advises short, descriptive file names. navy-merino-crew-sweater-front.jpg tells Google something. IMG_4031.jpg tells it nothing. Use hyphens, lower case and no stuffing.
5. Shoot more than one angle. For product rich results, Google recommends several high-resolution images, ideally in 16x9, 4x3 and 1x1 ratios. Front, back, detail and in-use shots also answer shoppers' questions before they ask.

Step 2: Add alt text everywhere

Alt text describes an image for screen readers and for search engines, and Google calls it the most important attribute for image metadata. Shopify keeps alt text in different places depending on where the image lives.

Product images

1. Open the product. In your admin, go to Products and click the product.
2. Click the image in the Media section, then click Edit alt text.
3. Write the description and click Save alt text. Repeat for every image, including variant images.

Collection and blog post images

1. Open the collection or blog post and find its featured image.
2. Click Update, then Edit image, enter the alt text and click Save.

Theme images, such as banners, image-with-text sections and logos, are stored in Content > Files. Open the file there and add alt text. Themes that output the file's alt text will pick it up wherever the image is used.

How to write alt text that works

Describe what the image shows, in plain words, using the language a shopper would search with. Each image of a product should say what's different about it.

Keep it to a short sentence. Google warns against stuffing keywords into alt text, and repeating the product name five times helps nobody. Purely decorative images, such as dividers or background textures, should have empty alt text so screen readers skip them.

The alt text fallback trap

Here is a Shopify detail most owners don't know. When an image has no alt text, the image_tag filter uses the resource title instead, for product, variant, collection, article and line item images. So a product with eight photos and no alt text outputs the product title eight times.

That looks fine in a quick audit, because no image is "missing" alt text. It's still eight identical descriptions of eight different photos, which tells Google and screen reader users nothing about the difference between the front, the back and the detail shot. When I audit image SEO, I check for repeated alt text, not just empty alt text.

Step 3: Check how your theme outputs images

A current Shopify theme handles most of this, but custom sections, page builders and older themes often don't. Open a product page, view the source, and check the main product image against this list.

1. It's an <img> element. Google finds images in the src attribute of <img> and doesn't index CSS background images. A product photo or hero set as a background won't appear in Google Images.
2. It has a src as well as a srcset. Google recommends always keeping a fallback src, because some crawlers don't read srcset. image_tag outputs both.
3. It's built with image_url and image_tag. For example {{ product.featured_image | image_url: width: 1200 | image_tag: sizes: '(min-width: 990px) 50vw, 100vw' }}. image_url accepts widths up to 5760 px but never upscales beyond the original.
4. It has width and height. image_tag adds them, which prevents layout shift as the image loads.
5. The first image isn't lazy loaded. image_tag lazy loads sections further down the page automatically. The main product image and the hero should load eagerly, because they're usually the Largest Contentful Paint element. My guide to Core Web Vitals on Shopify covers that fix in detail.

How Google finds your images

Shopify's sitemap.xml includes each product's primary image alongside the product URL. Additional product photos, collection images and blog images are found the normal way, by Google crawling the page and reading the <img> elements. That's enough for most stores, so I rarely recommend a separate image sitemap app.

Context matters as much as discovery. Google uses the text around an image to understand it, so a product image next to a real product description, a clear title and helpful headings is understood far better than one floating on a thin page. Google also recommends using the same image URL across pages, so it can cache it. Shopify does this naturally when you reuse an image from Files rather than uploading copies.

Shopify themes also include product schema markup, and Google recommends several high-resolution images for product results. Check what your theme outputs by running a product URL through Google's Rich Results Test and looking at the image property.

Images on a multilingual store

If you sell in more than one language, translate alt text along with the rest of the product content wherever your translation tool supports it. Google also suggests translating file names when you localize images. On Shopify, an image file is shared across languages, so a neutral, descriptive file name in your main language is the practical choice, with translated alt text doing the local work.

Common mistakes

• Relying on the title fallback, so every product photo has the same alt text.
• Keyword lists in alt text. Google treats keyword stuffing as spam, and it reads badly to screen reader users.
• Text baked into images. Sale messages and size charts as images can't be read by Google or translated. Put the words in HTML.
• Hero and product images as CSS backgrounds, which Google doesn't index and which load late.
• Lazy loading the first product image, which slows LCP.
• Renaming files that are already linked, which breaks the old image URLs.
• Paying for a compression app without checking what the CDN already serves.

Image SEO checklist

• Originals are sharp, one aspect ratio, around 2048 px on the long side, under 20 MB.
• File names are short, descriptive and hyphenated before upload.
• Every product image, including variant images, has its own alt text.
• Collection, blog and theme images have alt text, set in the product, collection, post or Content > Files.
• Decorative images have empty alt text.
• No repeated alt text across a product's photos.
• Product and hero images are <img> elements built with image_url and image_tag.
• Main product image and hero load eagerly. Images below them lazy load.
• Product pages have real descriptive text near the images.
• Alt text translated for every published language.

What to do next

Start with your ten best-selling products. Write proper alt text for every photo, check the theme outputs it, and fix the first-image loading. Then work through collections and theme images. You can run any page through the free Shopify store analyzer to spot images and pages that need work.

If you'd like it done across the whole catalog, my Shopify SEO work starts from $200 and covers alt text, theme image output and structured data together. Or send me your store for a free review first.

Frequently asked questions

Sources

1. Google image SEO best practices, Google Search Central
2. Product media types, Shopify Help Center
3. Adding keywords to your store (alt text), Shopify Help Center
4. Uploading files, Shopify Help Center
5. image_tag filter, Shopify.dev
6. image_url filter, Shopify.dev

Related services and work

Written by Ashraf Siddik

I'm a Shopify developer and CRO specialist. I have built and improved Shopify stores since 2018, completed more than 1,000 projects, and hold a 4.96 average rating across 719 client reviews.

About me · Client reviews