Use hyphens (-) instead of underscores (_) in filenames for optimal SEO performance.

Search engines like Google treat hyphens as word separators, improving how they parse and index your content. Underscores are viewed as part of a single word, which can hurt keyword relevance.

Impact on SEO

Hyphens signal distinct terms to crawlers, such as in “seo-file-naming.jpg”, boosting rankings for targeted searches [ from prior context].

Underscores like “seo_file_naming.jpg” reduce this separation, lowering discoverability.

Practical Tip

Always lowercase and pair with descriptive keywords: “wordpress-seo-guide.pdf”.

Test URLs post-upload to confirm readability across servers. Avoid mixing both in one naming scheme to maintain consistency.