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SEO Png

PNG (Portable Network Graphics) preserves image quality and supports transparency, making it a common choice for web graphics, logos, and screenshots.

If you have ever uploaded an uncompressed PNG for a large photo, you already know it can slow your pages and hurt Core Web Vitals.

Key points

  • Use descriptive, hyphen-separated filenames so search engines understand the image content.
  • Add relevant alt text to every PNG so screen readers and crawlers get context.
  • Compress PNG files before uploading to reduce page weight and improve load speed.
  • Prefer WebP or AVIF for large photos; PNG is best for graphics with transparency.

The same image, two different formats

A product page used a 2.5 MB uncompressed PNG for a photo of a chair. After converting to WebP, the file dropped to 400 KB with no visible quality loss. The page's Largest Contentful Paint improved from 4.2 seconds to 1.8 seconds, moving it into the 'good' Core Web Vitals range. The PNG was kept for the logo and icons, where transparency was needed.

Three common mistakes with PNG for SEO

  • Using PNG for large photos JPEG, WebP, or AVIF usually deliver smaller files with similar quality, reducing page weight and improving load speed.
  • Uploading uncompressed PNGs Uncompressed PNG files increase page weight and slow load times, directly affecting Core Web Vitals. As part of image SEO, always compress before uploading to reduce file size without losing quality.
  • Leaving filenames generic Generic filenames like 'image1.png' give crawlers no context about the image. Use descriptive, hyphen-separated names, and if you rename images, set up redirects from old URLs to preserve SEO value.

Three ways to optimise PNG for performance

  • Compress before uploading Use tools like ImageOptim or TinyPNG to reduce file size without losing quality. For technology companies, fast-loading pages are critical; compression helps meet performance benchmarks.
  • Add descriptive alt text Alt text helps screen readers and gives search engines context about the image content. Write descriptive, concise alt text that describes the image naturally, avoiding keyword stuffing.
  • Use responsive images Serve different sizes for different viewports using srcset to avoid loading large images on mobile.

Common questions

Should I convert WebP to PNG for SEO?

No, keep WebP for photos; PNG is better for graphics with transparency, not for general photos.

Is PNG better than JPEG for SEO?

Not for photos; JPEG is smaller. Use PNG only when you need transparency or sharp edges.

Sources

  1. Google Search Central – Image SEO best practices Official guidelines on image formats, alt text, and sitemaps.
  2. Screaming Frog – Image SEO Practical advice on image optimisation and file formats.
  3. SEO Analyse – PNG definition Definition and technical details of the PNG format.
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