Image optimization sounds like a big technical project, but it really comes down to a dozen habits. Run through this checklist each time you add images to a page and your site will be faster, more accessible and better prepared for search.
1. Start from the original
Always work from the highest-quality source file, not a copy that’s been resized or compressed before. Each generation of saving loses a little. See the common resizing mistakes.
2. Resize to the size you actually need
Find the widest space the image will fill and resize to about that width, or up to double it for sharp results on high-density screens. A 4000-pixel photo in an 800-pixel column is wasted weight. Our blog post image size guide has numbers.
3. Choose the right format
Photos: WebP or JPG. Graphics with sharp edges: PNG or SVG. Don’t use PNG for photographs. See the best image format for websites.
4. Compress sensibly
JPG or WebP quality in the 75 to 85 range is a good default. Check the result at full size rather than shrunk to fit. See the JPG quality guide.
5. Check the file size
As a rough guide, aim for under 200 KB for typical content images and under about 250 KB for a hero image. Heavier is sometimes fine for a key photo, but look closely at anything above 500 KB.
6. Name the file descriptively
Use lowercase words separated by hyphens that describe the picture. Do it before you upload. See naming image files for SEO.
7. Write real alt text
Describe the image for someone who can’t see it, briefly and specifically, without stuffing keywords. Decorative images get an empty alt. See our alt text guide.
8. Set width and height attributes
This stops the page from jumping around as images load. See how to set image width and height in HTML.
9. Lazy load images below the fold
Add loading="lazy" to images lower on the page, but not to the top image. See lazy loading images.
10. Offer responsive sizes if you can
Most WordPress sites do this automatically. If you hand-code, look at srcset and sizes.
11. Remove unneeded metadata
If you publish photos of places or people, check for location data. See what is EXIF data.
12. Test on a real phone
Open the page on a phone over mobile data if you can. Watch how it loads, whether images look sharp and whether anything jumps. Free tools like Google’s PageSpeed Insights show how your page performs and which images are slowing it down.
Why it all matters
Images are usually the heaviest part of a web page, and page speed affects both visitors and search. We dig into that in how image size affects SEO and page speed.
Make it a routine
You don’t need to remember all twelve every time. Pick a standard workflow: resize to your usual width, export as WebP or JPG at 80, rename, upload, add alt text. Do that every time and most of the list takes care of itself.
For the first four steps, our free image resizer does the heavy lifting in a single pass.