Does ThumbPress affect my SEO or page speed scores?

Yes but in a positive way.

Image weight is one of the biggest factors slowing down WordPress sites, and slow sites rank lower in Google. By compressing your images, converting them to WebP or AVIF, and cleaning up unused, duplicate, and oversized files, ThumbPress directly improves the metrics that influence SEO and page speed:

• Faster page load times
• Better Core Web Vitals scores, especially Largest Contentful Paint (LCP)
• Lower bandwidth usage
• A leaner, less bloated media library

Users running ThumbPress typically see noticeable improvements in PageSpeed Insights, GTmetrix, and Lighthouse scores after just one bulk optimization pass.