Internal images are all the image files—JPEGs, PNGs, WebPs, SVGs, and GIFs—that are hosted on your own domain. These visual assets are critical for creating an engaging user experience, but they are also powerful SEO assets that need to be audited and optimized. A comprehensive image optimization strategy goes beyond simple compression; it involves ensuring every image on your site is performant, accessible, and properly indexed by search engines.

Think of your internal images as part of your site’s core infrastructure. Just like your HTML and CSS, they need to be technically sound to support your SEO goals. A single, unoptimized image can slow down a page, while a missing alt tag can create an accessibility barrier. For a broader look at your site’s components, see our guide on the resources category.

An illustration of a photo gallery, representing the collection of internal images on a website.

The SEO Checklist for a Healthy Image Portfolio

A systematic audit of your internal images should focus on three key areas: performance, accessibility, and indexability. For a deep dive into Google’s recommendations, their Google Images best practices guide is the definitive resource.

  • Performance: Are your images slowing down your site? Check for resources category and ensure you are serving correctly sized images for their containers.
  • Accessibility: Can all users understand your images? Every meaningful image must have descriptive alt text to be accessible to screen readers.
  • Indexability: Can search engines find and index your images? Ensure your images are not blocked by `robots.txt` and that you are not using the `noimageindex` directive on pages where you want images to rank.

How to Audit Your Internal Images

A complete audit is the only way to get a full inventory of your visual assets and identify optimization opportunities. For more on the tools you can use, this guide from Moz on image optimization is a great starting point.

  1. Crawl Your Site: Use a tool like Creeper to discover every internal image URL on your website.
  2. Analyze the Image Report: Review the data for all discovered images. Filter and sort by file size to find the largest images that are slowing down your site.
  3. Check for Errors: Identify all images that return a 4xx or 5xx status code. These broken images need to be fixed immediately.
  4. Audit Alt Text: Review the list of images to find any that are missing alt text. Prioritize adding descriptive alt text to your most important, context-rich images.

Frequently Asked Questions

What is the difference between internal and external images?

Internal images are image files that are hosted on your own domain. External images are hosted on other domains, such as a CDN or another website. While both should be optimized, you have direct control over the optimization of your internal images.

How do I find all the internal images on my website?

The most effective way is to use a website crawler like Creeper. It will scan your entire site and compile a complete list of all internal image URLs it discovers, along with their status codes, file sizes, and the pages they appear on.

Is it better to host images on my own domain or a CDN?

For most websites, using a Content Delivery Network (CDN) is the superior choice for performance. A CDN can deliver your images to users from a server that is geographically closer to them, which significantly speeds up download times. However, the core optimization principles (compression, resizing, alt text) still apply regardless of where the image is hosted.

Are your images working for or against your SEO? Start your Creeper audit today to get a complete picture of your internal images.