Browser Compatibility
Choose how next-gen images (WebP/AVIF) are served to your visitors. This setting ensures that users always receive the most optimized file format supported by their specific browser.
Options
- Use rewrite rule (default)
Adds directives to the /wp-content/.htaccess file to detect browser support at the server level. If AVIF is supported, it is served first; otherwise, it falls back to WebP. If neither is supported, the original JPG/PNG is loaded. - Compatible rewrite rule (Beta)
An alternative set of rewrite rules for broader server compatibility. Try this if the standard “Rewrite Rule” fails to serve optimized images on your host. - Use picture tag
Replaces standard <img> tags in your site’s HTML with <picture> tags containing multiple source files. The browser then selects the best format it can display.
1. The picture tag method works for most browsers but does not support images loaded via CSS.
2. Select Use picture tag method when .htaccess rules cannot take effect, for example, on OpenLiteSpeed servers where a required restart is not possible.
Max dimensions
Automatically downscales oversized images during the upload process to optimize disk usage and loading speeds.
Example: if you set the width to 1280 px, any uploaded image wider than 1280 px will be scaled down to a 1280 px width while perfectly maintaining its original aspect ratio.
- Enter a maximum width and height in pixels.
Images larger than these values will be downscaled proportionally.
Setting a reasonable max dimension (e.g., 2560px) helps save significant disk space by preventing oversized original uploads.
EXIF data
Remove metadata embedded in your images, including geolocation, timestamps, authorship, and image summaries.
Options
- Keep (default):
Retains all original metadata within the image file. - Strip:
Removes all metadata from the image.
Stripping EXIF data helps protect your privacy and reduces the overall file size. However, this feature is only supported if Imagick is installed and used on your server.
Avoid larger files
Automatically delete AVIF and WebP images when they are larger than the original images to ensure the optimization process always yields a smaller file.
- If optimized file is larger, keep original:
Automatically deletes AVIF/WebP versions if they exceed the size of the original JPG/PNG files.
Format exclusions
Select the specific formats you want to exclude from conversion, and skip unnecessary processing for certain file types.
Options
- Do not convert PNG to WebP
- Do not convert PNG to AVIF
- Do not convert JPG to WebP
- Do not convert JPG to AVIF
Excluding formats is useful in specific scenarios, for example, when you have high-quality images that must remain in their original format to preserve specific metadata or transparency features.
Queue throughput
This setting determines how many WordPress image attachments—including the original image and all its associated thumbnails—are processed in a single AJAX cycle.
Options
- Process 5 images per batch (default):
A balanced setting for most web hosts. - Process 10 or 20 images per batch:
Best for high-performance servers to speed up bulk optimization. - Process 1 image per batch (safest):
Ideal for limited hosting environments to prevent timeouts.
1. If you experience server timeouts or ‘Gateway Timeout’ errors during optimization, choose ‘Process 1 image per batch (safest)’ to ensure stable processing.
2. Most hosting services limit AJAX execution to 120 seconds. If set to 1, the plugin processes 1 attachment (e.g., 1 original + 20 thumbnails) per cycle. At the default of 5, it can estimate ~300 images per hour, though actual speed depends on your server performance.
New Upload (Cron)
Define exactly when CompressX Pro should process and optimize newly uploaded images. Controlling this helps manage server resources and ensures a smooth workflow.
Options
- Process immediately on upload:
Optimization begins the moment an upload completes. You may notice a slight delay before the image is available in the library while real-time conversion takes place. - (Recommended) Delay processing:
Defers optimization by a specified time — 3, 10, or 30 minutes — after the upload. This is ideal for preventing workflow interruptions during high-volume uploading. - Scheduled processing window:
Delays the optimization of all new uploads until a specific daily time window (e.g., 12:00 AM to 6:00 AM). This is best for high-traffic sites to minimize server impact during peak hours.
Use Delay processing to keep your Media Library responsive while you are actively working. If you have a very limited server, use the Scheduled processing window to handle all conversions overnight.
Prioritize Images on Pages
This feature focuses resources on optimizing images that are currently being viewed by active visitors, rather than just following the standard chronological queue.
Options
- Process immediately when a page gets visitors:
Images on visited pages are optimized as soon as the page is accessed. Note that this may cause a brief delay in image availability while the real-time conversion completes. - Scheduled processing window:
Prioritized images are added to a queue and processed only during your specified daily time window (e.g., overnight) to reduce server load during peak hours.
Use this feature for sites with a large backlog of unoptimized images where you want the most popular content improved first, providing an immediate SEO and performance boost where it matters most.
Watermark (optional)
Automatically tag newly uploaded images and prepare recent uploads for batch watermarking later.
- Mark new uploads for watermarking:
When enabled, every new image you upload is automatically flagged and added to the watermarking queue for easy bulk processing.
Use this feature to save time by identifying new content for protection automatically, rather than manually selecting images in the Media Library.
Save Changes
To ensure your optimization preferences are applied, always click the Save Changes button at the bottom of the page after modifying any settings.
View More Settings
The General Settings page also provides a direct shortcut to navigate to advanced configuration areas for deeper control over folder management, thumbnail processing, and cleanup tools.
