Image SEO for Shopify: Alt Text, File Names & Compression

Photos do most of the selling on a Shopify store. They also quietly do most of the damage to your page speed and miss easy ranking wins along the way. Treat images as an SEO surface and three things change: you show up in Google Images, your pages load faster, and your store works for people using screen readers. Here's the order I'd tackle it in, starting with the part most stores get wrong.

Alt text: describe the photo, don't decorate it

Alt text is how search engines and screen readers know what an image shows. Say what's actually in the frame, name the product and one defining attribute, and write it the way you'd describe it out loud. Drop "image of" and "photo of," keep it short, and don't cram keywords in. "Tan suede ankle boots with block heel" earns its place. "boots shoes footwear womens boots cheap boots" gets you nothing and reads like spam.

File names that mean something

IMG_4821.jpg tells Google exactly nothing. Rename files before you upload so the name describes the image:

• Use blue-leather-crossbody-bag.jpg, not a camera string.
• Lowercase letters, hyphens between words. No underscores, no spaces.
• A few accurate words is plenty. You're labeling, not writing a headline.

Compress before you hit upload

Oversized images are the single most common reason a Shopify store feels sluggish, and speed feeds both rankings and conversions. Resize each image to roughly the size it'll display at instead of uploading a 4000-pixel original, then compress until the file is as small as it can be while still looking crisp on a retina screen. A product shot that loaded at several megabytes will usually drop to a fraction of that with no visible difference.

Pick the format that fits

WebP holds up at much smaller sizes than old JPEG or PNG files. Shopify already serves modern formats automatically where the browser supports them, but that doesn't excuse a bloated source file, so start lean. Reach for PNG only when you genuinely need transparency, like a logo over a colored band. For everything else a compressed JPEG or WebP is lighter.

Help the page paint faster

Lazy loading holds back off-screen images until a shopper scrolls toward them, so the first view renders quicker. Most current Shopify themes already do this. Make sure your images carry width and height attributes too, so the browser reserves the right space and the layout doesn't jump as things load. That jump, cumulative layout shift, is one of the Core Web Vitals Google watches. None of this is dramatic on its own; together it's the difference between a snappy store and a janky one.

The hard part is keeping it up at scale

Knowing the rules is the easy bit. Applying them to a few thousand images, photo after photo, is where it breaks down, and alt text is the first thing to get skipped during a busy product launch. Either build a checklist you actually follow at upload, or automate the repetitive parts, so every new image meets your standard instead of turning into next month's audit warning.

File names and compression are quick to handle as you upload. Alt text is the pillar that quietly rots across a growing catalog, which is why it's worth handing off. Seokai writes accurate AI image alt text in bulk and can apply it automatically the moment a new product is created, so that column of warnings stays empty without you touching each photo. Cover names and compression at upload, let automation own alt text, and your images will pull their weight for search as well as they do for sales.