Images are part of the main content on many pages, not decoration added after the article is finished. Good image SEO begins with choosing visuals that actually help the reader and making them technically accessible.
Quick Answer
Use relevant images, descriptive filenames, meaningful alt text, useful surrounding text, sensible dimensions and crawlable image URLs. Compress media without destroying quality and verify that lazy loading or scripts do not prevent discovery.
Choose Images That Add Information
A screenshot, diagram or real contextual photo should support the nearby section. Decorative stock images can make a page look fuller without helping the reader understand anything.
For tutorials, screenshots often work best when they show the exact interface or outcome being discussed.
Write Alt Text for the Image’s Role
Alternative text should describe useful information conveyed by the image. If the image is purely decorative, forcing keywords into alt text creates noise rather than accessibility.
Keep filenames readable before upload because they can become permanent media URLs.
Check Technical Delivery
Use responsive image sizes, compressed formats where appropriate, and predictable dimensions to reduce layout shift. Make sure crawlers can fetch important image URLs and that lazy loading still produces normal image elements.
Image SEO QA
- Is the image relevant to the section?
- Does alt text describe its useful content?
- Is the image compressed and appropriately sized?
- Can the image URL be fetched without authentication?
- Does the page reserve dimensions to reduce layout shift?
- Are image credits and rights records preserved where required?
Example: One Image, Three Different Jobs
A featured image may primarily help a reader recognize the article in a listing. A screenshot inside a tutorial may document an exact interface. A diagram may explain a relationship that is difficult to describe in text. Those images should not receive identical treatment because their informational roles differ.
For the screenshot, alt text should identify the important interface or state being shown. For the diagram, alt text should communicate the core relationship. A decorative featured image may need simpler alternative text—or none if it conveys no information beyond decoration.
Performance and Discovery Work Together
Large uncompressed images can slow loading, while aggressive compression can destroy the detail that makes a screenshot useful. Resize media close to the largest display size, use an appropriate format, and preserve enough quality for text and interface elements to remain readable.
Check the rendered page after lazy loading is applied. Important images should still appear as normal discoverable image elements, have stable dimensions to reduce layout movement, and sit near text that explains what the visual represents.
Common Mistakes
Avoid stuffing alt attributes with keywords, uploading multi-megabyte originals unnecessarily, using unrelated images simply to hit a media quota, or relying on a background image for content that needs accessible alternative text.
Watch the Topic in Context
SEO for Google Images
Google Search Central’s image SEO talk covers discovery, context and optimization practices for images in Search.
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