YandexImageResizer

What is YandexImageResizer?

YandexImageResizer is a specialized utility bot operated by Yandex LLC, a major Russian technology company that runs one of the largest search engines in Russia. This tool functions as a technical image processing bot that identifies, retrieves, and processes images from websites across the internet. First deployed around 2009, YandexImageResizer is classified as a utility crawler that specifically focuses on image content rather than general webpage indexing.

The bot works by scanning websites for image content, downloading images, and then processing them in various ways—primarily resizing them for different display contexts within Yandex services. When visiting a website, YandexImageResizer identifies itself through the user-agent string Mozilla/5.0 (compatible; YandexImageResizer/2.0; +http://yandex.com/bots). This identification allows website administrators to recognize its presence in their server logs.

Unlike general-purpose crawlers, YandexImageResizer has a very specific focus on image assets and typically doesn't crawl text content or other website elements. It operates from Yandex's server infrastructure, predominantly from Russian IP addresses.

Why is YandexImageResizer crawling my site?

YandexImageResizer visits websites primarily to process images that have been or will be displayed in Yandex's various services, such as search results, image search, or other Yandex products. If your website contains images that users might search for or that appear in Yandex search results, the bot will visit to process these images.

The frequency of visits depends on several factors, including how often your content appears in Yandex search results, how many images your site contains, and how frequently your image content changes. Sites with high visibility in Yandex search or with frequently updated image galleries may experience more regular visits.

The bot's crawling is generally considered legitimate when it's processing images that will be displayed in Yandex services. However, since Yandex is primarily focused on the Russian-speaking internet, websites targeting other markets might find these visits less relevant to their audience.

What is the purpose of YandexImageResizer?

YandexImageResizer serves a specific technical function within Yandex's ecosystem—optimizing images for display across various Yandex services. When users search for content on Yandex, the search engine often needs to display image thumbnails or optimized versions of images from websites. Rather than serving the original full-sized images (which could be slow to load or consume excessive bandwidth), YandexImageResizer processes these images into appropriate formats and sizes.

The bot supports Yandex's image search, regular search results with image previews, and potentially other Yandex services that display images from across the web. By creating optimized versions of images, it helps Yandex deliver a faster, more efficient user experience while reducing bandwidth requirements.

For website owners, this processing can indirectly benefit their content's visibility within the Yandex ecosystem, as properly optimized images may display better in search results and other Yandex services.

How do I block YandexImageResizer?

YandexImageResizer does not consistently respect robots.txt directives, according to available information. This means that standard robots.txt configurations may not reliably control its behavior. However, it's still worth implementing robots.txt rules as a first line of defense, as they may affect other Yandex bots.

If you wish to attempt blocking via robots.txt, you can add the following to your robots.txt file:

User-agent: YandexImageResizer
Disallow: /

Since robots.txt may not be fully effective, you might need to implement additional measures. Server-side blocking based on the user-agent string is one approach. This can be done through your web server configuration (like Apache's .htaccess files or Nginx configuration) to block requests from the YandexImageResizer user-agent.

For Apache servers, an example .htaccess rule might look like:

SetEnvIfNoCase User-Agent "YandexImageResizer" bad_bot
Deny from env=bad_bot

Alternatively, you could implement IP-based blocking for Yandex's IP ranges, though this approach requires maintenance as IP addresses can change over time.

Keep in mind that blocking YandexImageResizer may result in your images not appearing properly in Yandex search results or other Yandex services. If you target Russian-speaking markets, this could potentially reduce your visibility to users of these services.