Image Optimization

A free guide to the basics of optimizing images on your website.

Images have had a role in optimization since the early days of SEO. However, since these days most search engine’s now provide convenient image search options it has become a significant opportunity.

In addition to image specific searches Google’s shift to Universal Search introduced relevant images with-in regular search results making image optimization even more important.

Tactics to optimizing your images for search include applying relevant alt text, file naming and placement with-in relevant content.

Optimizing Images

Image Optimization details

Placement

Images should reside in the <body></body> of a document

Format

<img src=”optimized_file-name” alt=”optimized alt text“>

Image Size Limitations

Avoiding placing alt text on minor/small images

File Naming Limitations

Maximum character limit – 127* characters

Alt Text Limitations

Maximum character limit – none , avoid exceeding 30ish

Optimizing Image Alt Text

Alt tags are the textual description of an image that appears when your mouse is over an image. Alt text is also displayed on-screen when an image cannot load and is interpreted/repeated by screen readers for the visually impaired.

Since search engine spiders cannot see image content, alt text can provide relevancy to the image.

Image Alt Text optimization tips

  • Avoid stuffing alt text with unnecessary words or too many keywords
  • Avoid placing alt text on minor images (ie 1px images)
  • Avoid special characters or HTML tags with-in image alt text
  • Include relevant phrases in image alt text
  • Include alt text for images links – acts much like anchor text for text links

Optimized image alt text examples

Assuming the target phrase is “Free SEO Guide” here are a few examples of image alt text with varying qualities of optimization.

Poor Image Alt Text:
“picture”
“keyword 1, keyword 2, keyword 3…”

Better Image Alt Text:
“free seo guide banner – click here to read”

Best Image Alt Text:
“Free SEO Guide”

Optimizing Image file names

While alt text optimization is older and more practiced, using relevant phrases in your image file names is also  important and effective.

As with any optimization effort you don’t want to get carried away with keywords, but a natural use of relevant phrases in file names is not only good SEO, its also a good usability convention.

Image Naming optimization tips

  • Avoid stuffing file name with unnecessary words or too many keywords
  • Include relevant phrases in image file naming
  • Include hyphens - or underscores _ to separate keywords (IE avoid “hereismyseoimage.gif”)

Optimized file naming examples

Assuming the target phrase is “Free SEO Guide” here are a few examples of image file names with varying qualities of optimization.

Poor Image File Naming:
“img_345665-grfc.gif”

Better Image File Naming:
“banner_image_seo_guide.gif”

Best Image File Naming:
“free_seo_guide.gif”*
“free-seo-guide.gif”*
* use hyphens or underscores to separate words, not spaces