Best Image Sizes for Websites, Social Posts, and Thumbnails

Why dimensions matter

Image dimensions affect sharpness, cropping, layout stability, and load time. Uploading a 5000 px image for a 320 px card makes the page heavier without improving what users see.

Useful target sizes

Blog cover images often work well at 1600 x 900 or 1200 x 630. Open Graph previews commonly use 1200 x 630. YouTube thumbnails use 1280 x 720. Square social posts commonly use 1080 x 1080. Product grid images often use 1000-1600 px on the longest side so zoom views remain clear.

Workflow

Decide where the image will appear.

Resize to 1.5-2x the displayed CSS size for high-density screens.

Crop to the correct aspect ratio before compression.

Export WebP or JPG depending on platform support.

Check the final page on mobile, not only desktop.

Avoiding layout shifts

Set width, height, or aspect ratio in your page templates. This reserves space before images load and prevents text from jumping around.

Common mistake

Do not use one exported size for every placement. A full-width hero, a small card thumbnail, and a social preview need different crops and compression settings.