Record where the image appears and whether the problem affects every device or only a large or high-density display. Check the original upload's dimensions and compare them with the space the image occupies.

A large file size does not necessarily mean a sharp image, and a high pixel count does not repair an already blurred source. Start with the visual quality of the original rather than uploading the same poor source at a larger dimension.

1. Edit the page and select the Image block.
2. Review the available resolution choices, such as Medium, Large or Full Size, and choose one suitable for the intended layout.
3. Check width and height controls for distortion. Preserve the aspect ratio unless a deliberate crop is intended.
4. Preview the page at its largest practical display width and on a narrow screen.
5. Save and inspect the image actually requested by the browser after relevant caches are refreshed.

A thumbnail may be sharp but show the wrong crop, while a full image may show the whole subject but be inefficient for a small card. Review the theme's registered sizes and focal-point or crop controls when composition is the problem.

If a new theme expects a size that older uploads do not have, regenerate the relevant thumbnails after a backup and a small test. Reuploading every image creates new attachment records and can complicate existing references.

Temporarily compare the original file, WordPress-generated size and any CDN-optimised output. An optimisation service may apply its own compression or resize rule. Change one layer at a time so the cause remains clear.

Do not force full-size originals across the entire site merely to fix one image. Verify the specific layout and delivery rule, then use an appropriate size that balances readable detail with loading cost.

• Understanding WordPress responsive images
• Regenerating thumbnails after a theme change
• Preparing web images before uploading to WordPress
• Adding captions and image credits

• WordPress: Image Block
• WordPress: Edit Media