Erdo Image Optimizer: Compress & Convert to WebP/AVIF (SEO Audit, Alt Text, Lazy Load)

常見問題集

Is this just another image compression plugin?

No. Compression is only one part of what we do. The core feature is the Image SEO Auditor, which grades every image in your media library on 6 SEO criteria: filename quality, alt text presence, title quality, contextual relevance, missing dimensions, and usage status. Most plugins never touch any of this.

How do I reduce image file size in WordPress without losing quality?

Use Erdo’s Smart Quality mode. It automatically finds the lowest compression level where visual quality is still preserved, then converts your image to WebP or AVIF — both of which deliver 30-80% smaller file sizes compared to JPEG or PNG. You can also enable lossless mode for zero quality loss.

What is the difference between WebP and AVIF?

Both are modern image formats far smaller than JPEG or PNG. WebP offers broad browser support (all major browsers since 2020) and fast encoding. AVIF is newer and typically 20-30% smaller than WebP at the same visual quality, but requires PHP’s GD library compiled with libavif support. Erdo supports both — pick the one that fits your server and audience.

How do I add alt text to all my WordPress images at once?

Use the Bulk Alt Text feature in the dashboard. Erdo scans every image missing alt text and automatically generates descriptive alt text from its filename. You can review and edit before saving. For images with meaningful filenames like blue-running-shoes.jpg, the generated alt text is immediately usable.

How do I convert all images to WebP in WordPress?

Go to Erdo’s dashboard, click Bulk Convert, choose WebP as the target format, and start the queue. Conversion runs in the background via WP-Cron — you can close the browser tab and let it finish. For large libraries (1,000+ images), the WP-CLI command wp erdo convert is the fastest option.

What makes the SEO Auditor different from other plugins?

Most “SEO” image plugins only check for missing alt text. Erdo’s auditor checks 6 distinct criteria and gives each image a score from 0 to 6 with specific reasons for any deductions. You get an actionable list, not a vague percentage.

How do I serve WebP images in WordPress?

Erdo handles WebP delivery automatically. On Apache servers, it writes .htaccess rewrite rules that transparently serve WebP versions to compatible browsers with zero code changes. On NGINX or other servers, it falls back to a PHP <picture> element rewriter that wraps your images with WebP source tags — no server configuration needed.

Will my original images be lost after conversion?

Never. Every original is automatically backed up to an _erdo_backup/ subfolder before conversion. You can restore any image to its original with a single click from the dashboard.

Does it work with all hosting providers?

Yes. WebP delivery works via .htaccess rewrite rules on Apache hosts. For NGINX or other servers, the plugin automatically falls back to a PHP-based <picture> element rewriter — no server configuration required.

Can I convert my entire existing media library?

Yes. Use the Bulk Convert feature from the dashboard. Processing runs in the background via WP-Cron, so you can close the browser tab and let it finish. For large libraries, the WP-CLI command wp erdo convert is recommended.

How do I find unused images in WordPress and delete them?

Open the Unused Media tab in Erdo’s dashboard. The plugin scans every image in your media library against all posts, pages, and ACF fields. Any image that appears nowhere on your site is flagged as unused. You can review the list and delete in bulk — freeing disk space and removing orphaned files that confuse search crawlers.

Does the filename sanitizer affect images I have already uploaded?

The automatic sanitizer applies to new uploads only. For existing images with messy filenames like IMG_1234 (copy).JPG, use the Bulk Rename feature in the dashboard — it renames files on disk, updates all database references, and prevents broken links automatically.

Does it support AVIF?

Yes. AVIF conversion is available in addition to WebP. AVIF typically produces 20-30% smaller files than WebP at the same visual quality. AVIF encoding requires PHP’s GD library compiled with libavif support, which most modern hosts provide.

Does it support HEIC and HEIF images from iPhones?

Yes. Erdo can convert HEIC/HEIF photos (the default format on newer iPhones) to WebP or AVIF via PHP’s Imagick extension. This requires Imagick to be installed on your server — most managed WordPress hosts include it by default.

Is it compatible with WordPress Multisite?

Yes. A dedicated Network Admin settings page lets you define default quality and format across all sites in the network.

Does it have a REST API?

Yes. Erdo exposes two REST endpoints: /wp-json/erdo/v1/stats returns optimization statistics (total images, conversion rate, space saved) and /wp-json/erdo/v1/audit returns the full SEO audit results. Both are useful for headless WordPress setups or custom reporting dashboards.

Does it integrate with a CDN?

Yes. Erdo includes a BunnyCDN integration that automatically uploads converted images to your BunnyCDN storage zone. Configure your Storage Zone name, API key, and hostname in the Settings tab to enable it.