You’ve just written a killer blog post or service page. The words are flowing, the call-to-action is solid, and you’ve even remembered to update your meta description (go you!).
Then comes the image. You drag in that stock photo, hit upload, and move on with your life.
But that innocent-looking image? It might be slowing your site, confusing Google, and blowing your shot at ranking on page one. And yeah… I’ve been there. Back in the day, I treated images like a “nice-to-have”, something that made the page look pretty, instead of the SEO powerhouses they actually are.
So, consider this your no more excuses moment, because this SEO Image Checklist is here to save your site’s speed, rankings, AND user experience.
Want to skip straight to the good stuff?
Download the SEO Image Checklist here and keep it handy every time you hit “upload.”
Inside this post, I’m walking you through exactly what to do before you upload any image.
Choose the Right Image (Don’t Just Upload Anything)
Look, I know it’s tempting to grab the first vaguely-relevant stock photo you find and slap it onto your blog post like a Band-Aid. But if your image has nothing to do with your content (or worse, shows up on 900 other websites), you’re missing a huge opportunity to boost your SEO and your brand vibe.
So before you upload that typing on laptop photo (you know the one 🙃), run through this list:
Make it Relevant
Your image should support what you’re saying, not just sit there looking pretty.
If your blog post is about time-saving workflows, don’t drop in a photo of someone doing yoga on a mountain. That’s not “time-saving,” that’s “spirit quest”.
Keep It High-Quality
This one’s non-negotiable. Blurry, stretched, or pixelated images scream, “I don’t know what I’m doing.”
Always upload sharp, clean visuals, and double-check how they look on desktop and mobile.
Avoid Stock Photo Overload
Yes, stock images are convenient. But if you’re using the same photo as everyone else in your niche? You’re blending in, not standing out.
Try to mix in:
- Custom brand photography
- Screenshots or mockups
- Branded graphics or illustrations
- Creating images in ChatGPT or Canva’s Magic Media
And if you do use stock images, don’t just drag and drop, make them your own:
- Add a colour overlay or brand filter so it fits your palette
- Crop creatively to focus on one detail
- Layer text or icons to give context
- Use Canva or Photoshop to add your logo, brand patterns, or a grain texture to stop it looking too squeaky clean
Okay, don’t judge, but I did a very quick example below just to show the difference between a stock image that anyone on the internet can use vs spending a few mins editing it to look more unique to your brand.
Check Permissions (Seriously)
Just because it’s online doesn’t mean it’s free to use.
Make sure you have the correct licenses or use royalty-free sites like Unsplash, Pexels, or (if you’re fancy) paid libraries like Adobe Stock.
If you create your own graphics or shoot your own photos? You’re not just levelling up your branding, you’re also owning the rights and keeping competitors from using the same visuals.
Resize & Compress Before Uploading
Because your 3000px hero image doesn’t need to be carrying that much emotional baggage
Here’s the deal: massive image files are SEO kryptonite. They slow your site down, frustrate your users, and make Google quietly judge you from a distance.
Before you upload anything, check the actual display size it needs to be. If the image is only showing at 400px wide on the page, there’s zero reason to upload the original 5000px file straight out of Canva or your camera.
Once you’ve resized it to fit your layout, it’s time to squash that file down to a web-friendly size. Use tools like TinyPNG, ImageOptim, or Squoosh to compress without destroying the quality. They work magic in the background so your image still looks great, but loads lightning fast.
Aim for under 150KB per image, especially for anything that appears above the fold. Your future site visitors (and your Core Web Vitals) will thank you.
Rename Your File Properly
If you’re still uploading images with names like “Screenshot_2023-08-04_at_11.37.22.png” — this is your intervention.
Google (and screen readers) actually read your file names. So when you upload something with zero context, you’re missing an easy SEO win. Descriptive file names help search engines understand what your content is about , and can even help your images show up in Google Images (hello, extra traffic 👋).
Here’s how to do it right:
- Use clear, descriptive names that reflect the image content
- Include relevant keywords (naturally)
- Separate words with dashes, not underscores (Google treats dashes as space; underscores, not so much)
Example:
Instead of: IMG_3827.jpg
Try: edinburgh-modern-kitchen-design.jpg
It takes 10 seconds, but it’s one of those small habits that compound big results over time, especially if your site is image-heavy.
I’ve actually written a whole blog on how and what to name your images for SEO (with examples), if you want to go deeper.
Use the Right File Format
Each image format has its own strengths, and picking the right one can seriously affect your page speed, quality, and user experience. So here’s the lowdown:
- JPEG (or JPG) → Best for photos. Small file sizes, good quality, loads quickly. Ideal for blog post images, headshots, and anything with lots of colour or detail.
- PNG → Best for graphics with transparency (like logos, icons, or illustrations that need a clear background). Slightly heavier than JPEGs.
- WebP → Smaller file size and better quality than both JPEG and PNG. Plus, it supports transparency! If your website platform supports it (like WordPress, Shopify, or Showit), use it.
- SVG → Best for simple vector graphics like logos or icons. Super lightweight and scalable without losing quality. Plus, it stays crisp on all screen sizes.
Fill In the Alt Text
Alt text is one of those things that feels optional… until you realise it’s helping with both accessibility and SEO.
It tells screen readers what the image shows and gives Google extra context to understand your content. But most people either skip it completely or stuff it full of keywords. Let’s not do that!
So what makes good alt text?
- Describe the image clearly and simply
- Include a relevant keyword if it fits naturally
- Keep it short — one sentence is enough
- Leave it empty (alt=””) if the image is purely decorative
Let’s use the image below as an example:
❌ Bad alt text: SEO expert website designer London
✅ Good alt text: Google Search Console report showing increased clicks and impressions from recent SEO services for a service-based business
Why is the second one better?
Because it clearly describes what’s in the image and ties it to the context of the page, without sounding like you’re trying to rank for 12 things at once. I’m also still getting the keyword “SEO services for a service-based business” naturally.
Use Image Dimensions & Lazy Loading
If you’ve ever loaded a web page and watched the text shift halfway down the screen as the images catch up — that’s a layout shift. And yes, it’s annoying. But more importantly? Google hates it.
To keep things running smoothly (and scoring better on Core Web Vitals), always:
- Set image dimensions (width and height) in your code or CMS. This tells the browser how much space to reserve before the image loads.
- Turn on lazy loading. This defers loading off-screen images until the user scrolls down. Faster load time upfront, less pressure on your server, happier users. Most modern platforms (like WordPress, Showit, Shopify) have this built in, you just need to make sure it’s enabled.
Add Context with Captions & Surrounding Text
Google doesn’t just look at your image, it looks at the text around it too.
If your image is just floating there with zero explanation? You’re wasting an opportunity.
Here’s what to do:
- Write content that actually relates to the image
- Add a caption if it makes sense, people do read them
- Use keywords naturally around the image, not just in the file name or alt text
A screenshot showing client results? Tell people what they’re looking at and why it matters.
Images don’t speak for themselves. Help them out.
Organise with Structured Naming & Folders
Your media library shouldn’t look like your downloads folder. (Yes, I said it.)
A cluttered mess of “brandphoto233(2).jpg” and random Canva exports? That’s how you end up re-uploading the same image 5 times and wondering why your site’s storage is full.
Keep it tidy with:
- Consistent naming conventions — same format, every time (e.g. service-name-client-name-year.jpg)
- Folders by topic or page — blog images, testimonials, banners, etc.
- Keyword-friendly file names — helpful for both humans and search engines
A tidy library = way easier updates later. No more “Where did I save that cute brand photo from 2024?” meltdown. This might feel small, but it makes scaling your content (and your sanity) a whole lot easier.
Image Schema (Structured Data)
Want your images to really stand out in search results? This is where Image Schema comes in.
Image Schema (specifically the ImageObject type) is a bit of structured data you can add to your site’s code to help Google understand and index your images properly. It’s what can lead to enhanced search results, like image-rich snippets.
Do you need it? Not always.
But if your site is image-heavy (think blogs, portfolios, product pages) it’s worth it.
CDN Usage for Image Delivery
If your website serves visitors from all over the world, a Content Delivery Network (CDN) is a no-brainer.
A CDN stores copies of your images on servers around the globe, so when someone visits your site, they load the version that’s closest to them — which means faster loading and less lag.
Why it matters:
- Speeds up image load times for international visitors
- Reduces strain on your main server
- Many CDNs also auto-optimise your images (yes please)
Popular options:
- Cloudflare (free + paid plans)
- ImageKit
- Cloudinary
Most website platforms and hosts let you connect a CDN with just a few clicks, or they might already include one behind the scenes. Either way, check!
You’re Either Optimising Your Images or You’re Losing Traffic
Let’s not sugarcoat it: if you’re uploading giant, badly named, contextless images with zero alt text… you’re literally making your site harder to find and slower to load.
Your content deserves better.
Image SEO isn’t just for the algorithm, it’s about making your site faster, more accessible, and more professional. It’s the difference between looking polished and looking DIY.
I’ve pulled everything from this post into a quick SEO Image Checklist, so you’ve got something to refer back to before you hit upload (maybe even add it into your SOPs)
And if this all feels like another thing you should be doing but realistically won’t? That’s cool! Hand it off. I help service-based business owners sort this stuff properly so their content actually gets seen.
Check out my seo services or get in touch and let’s make your website work with you, not against you.
Quick Fire FAQs on Optimising Website Images for SEO & UX
What’s the best size for website images?
It depends on where they sit, but as a rule of thumb, hero images should be no more than 2000px wide and under 200KB in file size. Resize to match the display dimensions and compress before uploading.
How do I know if my images are slowing down my site?
Run a quick audit using tools like PageSpeed Insights, GTmetrix, or Lighthouse. They’ll flag oversized images and show you what’s dragging down your load time.
What’s the difference between alt text and image captions?
Alt text is for screen readers and search engines, it describes what’s in the image. Captions are visible to users and offer context or commentary.
Is WebP better than JPEG or PNG?
Yes, WebP usually delivers smaller file sizes and better quality, with support for transparency and animation. It’s a great default format for most web images now.
Should my image alt text match the file name?
Nope. They should work together, but not be identical. Use descriptive file names for SEO, and alt text to accurately describe the visual content.
How often should I review my site’s images?
At least once a quarter, especially if you run a blog, portfolio, or content-heavy site. Regular audits help catch bloated files, broken links, and missed SEO wins.
Can I use AI to write alt text?
Yes, tools like ChatGPT or image recognition APIs can help generate alt text. But always do a manual check for accuracy and tone before hitting publish.
Do infographics need SEO too?
Definitely. Give them keyword-friendly file names and alt text, and wherever possible, include a text version or summary nearby for both SEO and accessibility.
