If a site audit has just flagged 200 missing alt tags, the short answer is this. For a one off clean up under a few hundred images, doing it manually gives you better quality and stronger SEO services results. For anything larger, or for an ongoing site where new images get added weekly, an automated or semi automated approach is the only realistic option. Most agencies end up using a mix of both, and that is usually the right call.
I’ve sat in front of this exact problem more than once. A client comes in with a product catalogue or an image heavy blog, runs a Screaming Frog crawl, and the number that comes back is always bigger than they expected. Two hundred is a common figure. It sounds daunting, but it is entirely fixable in a weekend if you approach it properly.
Why missing alt tags matter in the first place
Alt text does three jobs. It describes an image to screen readers for accessibility, it gives Google something to index when it cannot see the image, and it can nudge rankings in Google Images and standard search results. Google has confirmed that descriptive alt text helps its systems understand image context, which is why it remains a basic part of any SEO services checklist. Missing it entirely does not tank your rankings overnight, but it does leave value on the table, particularly for ecommerce sites relying on product image search.
The manual approach
Going through images one by one in your CMS gives you full control over tone, keyword relevance, and accuracy. You can describe exactly what is in the image and tie it naturally to the page topic, which matters if that page is also being pushed through a PPC marketing agency campaign and needs consistent messaging across paid and organic.
The downside is time. At roughly two to three minutes per image once you include finding it, writing text, and saving, 200 images could take you the best part of a working day.
The automated approach
Plugins like Image SEO for WordPress, or bulk tools inside Shopify and Squarespace, can generate alt text using the image file name, surrounding content, or basic AI image recognition. Some newer AI tools will actually look at the image and describe it reasonably well.
The catch is accuracy. Automated tools sometimes produce generic or slightly odd descriptions, and they rarely understand brand context the way a human does. They are fast though, and fast matters when you are managing image heavy campaigns across Google Ads agency work and social channels at the same time.
| Factor | Manual | Automated |
| Speed | Slow, roughly 200 images in a day | Fast, hundreds in minutes |
| Accuracy | High, brand and context aware | Variable, sometimes generic |
| Cost | Time cost only | Tool subscription, often low monthly fee |
| Best for | Under 100 images, high value pages | Large catalogues, ongoing uploads |
| SEO value | Stronger, more targeted | Adequate, better than nothing |
A practical middle ground
What tends to work best is running the automation first to close the gap quickly, then manually reviewing and rewriting alt text on your top 20 or 30 highest traffic or highest converting pages. This is the same logic we apply across social media advertising agency work, where automation handles volume and a human handles anything customer facing. If you run image led ads through Facebook ads agency or LinkedIn advertising campaigns, the same product images often live on your site too, so it is worth prioritising those first.
FAQs
Does missing alt text hurt my Google rankings directly?
Not directly, but it removes a signal Google could otherwise use, and it hurts accessibility, which increasingly factors into overall site quality.
Can I just use AI to write all my alt text?
You can, and it is far better than nothing, but review anything customer facing or high traffic manually afterwards.
How long should alt text actually be?
Aim for around 125 characters. Describe the image plainly, include a relevant keyword only if it fits naturally, and avoid stuffing.
What if an image is purely decorative?
Leave the alt attribute empty rather than missing it entirely. An empty alt tag tells screen readers to skip it, which is correct behaviour.
If you would rather have someone else run this audit and fix it properly, that is exactly the sort of technical groundwork our SEO services team handles as standard. Get in touch and we will tell you honestly whether your 200 missing tags need a weekend or a proper clean up plan.
