Google typically selects an image from a webpage to use as a preview based on several factors, such as image dimensions, file type, and its relevance to the rest of the page’s content. If Google is pulling a PNG file as a preview, it might be due to the following reasons:
Image Size and Quality: A PNG image might be deemed the most suitable if it has an optimal size and quality compared to other available images on the page. Google tends to prioritize images that are large, high-quality, and have an aspect ratio that fits its preferred dimensions for thumbnails and previews.
File Format Preference: While JPEGs are commonly used for photographs due to their compression capabilities, PNGs offer lossless compression and are commonly used for graphics with text, logos, or images requiring transparency. The specific use case might make a PNG more preferable in certain contexts.
Image Placement and Markup: The HTML structure and placement of the image can play a significant role. If the PNG image is prominent, placed in key sections of the page (like the top), or marked with schema.org properties, it might be prioritized by Google’s algorithms.
Alt Text and Metadata: Images with rich, descriptive alt text and appropriate metadata can be more likely to be picked up by search engines as relevant content to display.
How to Fix This Issue:
Optimize Other Images: Ensure that other images on your page that you prefer Google to use for previews are well-optimized in terms of size, loading speed, and quality. They should also be prominently placed in your page layout.
Use Descriptive Alt Text: Provide descriptive alt text for the images you want to prioritize. Good alt text improves your site’s SEO and helps search engines understand the context of your images.
Implement Structured Data: Use structured data such as Open Graph tags or schema.org to explicitly specify which image you would like to represent your page in link previews. This provides additional context to search engines and social media platforms.
Ensure Fast Image Loading: Optimize images for faster loading, as page speed can influence image selection. Utilize modern image formats like WebP alongside PNG and JPEG.
Check URL Structure and Accessibility: Make certain your selected image is not blocked from indexing by checking robots.txt and ensuring proper URL structure.
Making these adjustments gives you better control over which images Google uses as previews, improving the alignment of the displayed visual content with your brand and messaging strategies.
