Image SEO: Auto ALT Text & Optimization Guide
Improve your image search rankings and accessibility with automatic ALT text generation, title attributes, and image sitemaps. This guide covers setup, templates, and best practices.
Image SEO is available on the Free tier and above — no license required.
What SEObolt Does for Images
| Feature | How It Works |
|---|---|
| Auto ALT Text | Automatically fills in missing ALT attributes using templates |
| Auto Title Attribute | Optionally generates title attributes for images |
| Filename Cleanup | Strips hyphens/underscores and capitalizes words |
| Image Sitemap | Generates /sitemap-images.xml with all images and their ALT text |
| SEO Analysis | Checks for missing ALT tags and keyword usage in images |
Why Image SEO Matters
- Accessibility -- Screen readers use ALT text to describe images to visually impaired users
- Google Image Search -- Proper ALT text helps images rank in Google Images
- SEO Score -- Missing ALT tags penalize your SEO score in SEObolt
- Context -- ALT text helps search engines understand what's on your page
Setup
Go to SEObolt > Settings > Images and configure:
| Setting | Default | Recommended | Description |
|---|---|---|---|
| Auto ALT Text | ON | ON | Generate ALT for images that don't have one |
| ALT Template | %filename% |
%filename% |
Template for auto-generated ALT text |
| Auto Title | OFF | OFF | Generate title attribute (optional -- most sites don't need this) |
| Title Template | %filename% |
%filename% |
Template for title attribute |
| Strip Hyphens/Underscores | ON | ON | Converts "blue-running-shoes" to "blue running shoes" |
| Capitalize Words | ON | ON | Title-cases the output |
ALT Text Templates
Available Variables
| Variable | What It Outputs | Example |
|---|---|---|
%filename% |
Cleaned image filename | "Blue Running Shoes" |
%post_title% |
Title of the post containing the image | "Best Running Shoes 2026" |
%site_name% |
Your site title | "My Store" |
%category% |
Primary category of the post | "Footwear" |
%focus_keyword% |
Post's focus keyword | "running shoes" |
Template Examples
| Template | Output For blue-shoes.jpg |
|---|---|
%filename% |
"Blue Shoes" |
%filename% - %site_name% |
"Blue Shoes - My Store" |
%post_title% - %filename% |
"Best Running Shoes 2026 - Blue Shoes" |
%focus_keyword% - %filename% |
"running shoes - Blue Shoes" |
Start with %filename% -- it's the most natural and descriptive (assuming you name your files well).
How Auto ALT Text Works
Image uploaded or inserted
You upload an image or insert one in the editor.
SEObolt checks for ALT attribute
SEObolt checks if the image has an ALT attribute set.
Empty ALT gets generated
If ALT is empty, SEObolt generates one using your template.
Existing ALT is preserved
If ALT is already set, SEObolt leaves it alone (never overwrites).
Auto-generation happens on page render, not in the database. Your original image metadata isn't modified.
SEO Analysis Image Checks
SEObolt's content analysis checks for these image-related items:
| Check | Points | How to Pass |
|---|---|---|
| Has Images | Included in content quality | Add at least 1 image to your content |
| ALT Text Present | 5 pts | All images must have ALT attributes |
| Keyword in ALT | Included above | Your focus keyword appears in at least 1 ALT tag |
| Image File Size | Flagged if issues | Images should be under 500KB |
Image Sitemap
SEObolt generates an image sitemap at /sitemap-images.xml containing:
- Image URL
- ALT text (used as caption)
- Title attribute
- Associated page URL (the page the image appears on)
Enable: SEObolt > Settings > Sitemap > Image Sitemap toggle
This helps Google discover and index your images for Google Image Search results.
Best Practices for Image File Names
Since %filename% is the default ALT template, naming your files well is critical:
| Bad Filename | Good Filename |
|---|---|
IMG_3847.jpg |
blue-running-shoes.jpg |
DSC0001.png |
chocolate-cake-recipe.png |
screenshot-2026.png |
seobolt-dashboard-overview.png |
photo1.jpg |
downtown-chicago-office.jpg |
Use hyphens between words (not underscores or spaces). Be descriptive but concise. Include relevant keywords naturally. Name files BEFORE uploading -- WordPress uses the filename as the default title.
Troubleshooting
ALT Text Not Auto-Generating
- Check setting -- SEObolt > Settings > Images > Auto ALT Text must be ON
- ALT already exists -- SEObolt only fills EMPTY ALT attributes. If any value is set (even a space), it won't overwrite.
- Page builder content -- Some page builders store images differently. ALT text from the builder takes priority.
- View page source -- Check the actual HTML output to see if ALT is populated
ALT Text Shows Raw Filename (With Hyphens)
- Check Strip Hyphens/Underscores -- Must be ON in Settings > Images
- Check Capitalize Words -- Enable for cleaner output
- Both settings should be ON by default
Images Not Appearing in Google Image Search
- Check image sitemap -- Visit
yoursite.com/sitemap-images.xmlto verify it loads - Check image accessibility -- Images must be publicly accessible (not behind login)
- Check robots.txt -- Image directories must not be blocked
- Wait -- Google Image indexing can take days to weeks
- Use descriptive ALT text -- Generic ALT text ("image" or "photo") won't help
Image Sitemap Is Empty
- Check toggle -- SEObolt > Settings > Sitemap > Image Sitemap must be ON
- Check for images -- Posts must contain images for them to appear
- Flush permalinks -- Settings > Permalinks > Save
SEO Score Penalizing for Missing ALT Text
- Check actual HTML -- View source to see if ALT is really missing
- Manual ALT preferred -- Write custom ALT text for important images rather than relying on auto-generation
- Include focus keyword -- At least one image ALT should contain your focus keyword
Image Optimization Tips
Beyond ALT text, these practices improve image SEO:
File Format
| Format | Best For |
|---|---|
| WebP | Best compression + quality balance (recommended) |
| JPEG | Photos and complex images |
| PNG | Graphics, logos, screenshots |
| SVG | Icons and simple graphics |
File Size
- Keep images under 500KB (ideally under 200KB)
- Use an image compression plugin (ShortPixel, Imagify, Smush)
- Serve images in WebP format when possible
Dimensions
- Don't upload images larger than needed
- For blog content: 1200px wide is usually sufficient
- For featured images: Match your theme's recommended dimensions
Frequently Asked Questions
"Does auto ALT text replace writing my own?"
No. Auto ALT text is a fallback for images you haven't manually labeled. For important images (featured images, product photos, infographics), always write custom ALT text.
"Will this slow down my site?"
No. ALT text generation happens during page render and adds negligible overhead.
"Should I include my focus keyword in every image ALT?"
No. Include it in ONE image ALT tag naturally. Stuffing the keyword into every image looks spammy to Google.
"What about decorative images?"
Purely decorative images (borders, spacers) should have an empty ALT attribute (alt=""). SEObolt's auto-generation won't fill these if you set them to empty in the editor.