Features marked (Pro) require the SPINX Digital Image Converter Pro add-on.
SPINX Digital Image Converter converts JPEG, PNG, and GIF images in your WordPress Media Library to the WebP format, including the thumbnail sizes WordPress generates. Conversion runs locally on your server using PHP’s GD or ImageMagick libraries. Original files are preserved so they can be restored.
The admin screens live under the WebP Optimizer menu item, where you can manage all plugin option like dashboard, settings, bulk convert and logs.
The Pro version of SPINX Digital Image Converter Pro unlocks additional advanced functionality, including:
SPINX Digital Image Converter Pro does not upload your images to any external service for processing and does not collect visitor data from your website.
All image conversion, optimization, compression, and related processing are performed locally on your WordPress website using your server’s available resources.
| Requirement | Value |
|---|---|
| WordPress | 6.2 or newer |
| PHP | 8.0 or newer |
| Image library | GD with WebP support (imagewebp) or ImageMagick with WebP support |
If no supported image library is detected, the plugin shows an admin notice: “SPINX Digital Image Converter: No supported image library found. Please enable GD or ImageMagick in your PHP configuration.” The Settings screen shows which engines your server supports.
The Dashboard shows live statistics pulled from the plugin’s data:
| Tile | Meaning |
|---|---|
| Total Images | All images in the Media Library |
| Convertible Images | JPEG/PNG/GIF that can still be converted |
| Converted | Images that now have a WebP version |
| Pending | Images queued and waiting to convert |
| Failed | Images that could not be converted |
| Already WebP | Images already in WebP (no conversion needed) |
| Unsupported Images | File types the plugin does not convert |
| Storage Saved | Total space saved, in MB |
SPINX Digital Image Converter Pro includes additional advanced features that are available in the Pro version of the Plugin.
Once the Pro version is installed, all included features are immediately available within your WordPress dashboard.
Updates and improvements for the Pro version are provided through standard Plugin update methods. When a new version is released, it can be updated from the WordPress admin dashboard.
No activation, setup, or additional configuration is required to use the Pro features.
The free version of SPINX Digital Image Converter Pro provides a set of core settings to configure image conversion, optimization, and related functionality.
When the Pro version is installed, additional advanced settings become available within the same settings interface, extending the capabilities of the plugin without requiring a separate configuration process.
Choose the library used for image conversion: Auto (default), GD, or ImageMagick. Each option indicates whether it is supported on your server. When Auto is selected, the plugin automatically chooses the best available engine.
When enabled (default), newly uploaded JPEG, PNG, and GIF images are automatically converted, including all generated thumbnail sizes.
When enabled (default), the plugin serves WebP images by replacing image URLs (including responsive srcset sizes) wherever a WebP version exists.
The Free version uses a fixed 75% WebP quality for balanced compression and image quality.
Enables advanced bulk processing tools for converting or restoring multiple images with improved control and monitoring.
Adds a customizable quality slider (1–100%) with saved settings. Higher values produce better image quality with larger file sizes. The plugin may also apply internal optimization adjustments based on image size.
Adds processing controls that allow bulk conversion and restore operations to be paused and resumed without restarting the process.
Automatically disables conversion and restore buttons when no valid action is available, improving usability and preventing unnecessary actions.
Provides an interactive before/after comparison slider for converted images, including file size savings, dimensions, and visual quality differences.
Adds a centralized library view for managing converted, pending, failed, and restored images.
Allows bulk restoration of all optimized images back to their original versions in one action.
Enhances the dashboard with real-time statistics, including converted, failed, pending, and processed image counts.
Safely add SVG (vector) images to WordPress, which blocks them by default for security reasons. The Pro add-on enables SVG uploads with built-in sanitization: every uploaded SVG is automatically cleaned of potentially malicious content (scripts, embedded objects, event handlers, remote references, and javascript: URLs) before it’s saved, using a trusted whitelist-based sanitizer.
SVGs behave like first-class media: thumbnails render correctly in the Media Library grid, list, and modal views, dimensions and file details display properly, and SVGs can be used as featured images. The feature is secure opt-in (off until you enable it) and role-gated — you choose which user roles are allowed to upload SVGs, with administrators always included. It’s managed from its own dedicated SVG Support settings screen, separate from the WebP conversion settings, so SVG handling stays cleanly independent.
Provides clickable dashboard statistics and a dedicated Images management screen for filtering, converting, restoring, and troubleshooting image conversions.
Take control over which image formats get converted. The Pro add-on adds per-type toggles for JPEG, PNG, and GIF in your settings, letting you enable or disable conversion for each format independently.
These settings are respected everywhere conversion happens — automatic conversion on upload, bulk conversion, the per-image Convert action in the Media Library, and the WP‑CLI command — as well as in the dashboard counts, so your “Convertible” and “Pending” totals always reflect the formats you’ve chosen. When a type is disabled, the plugin clearly tells you so: the Bulk Convert page shows which types are turned off, and disabled images display a “Conversion disabled” note instead of a Convert button (you can still restore them). By default all three formats are enabled, so conversion works out of the box.
See exactly what WebP conversion did to your images with a built-in before/after comparison tool. On any converted JPG, PNG, or GIF, click Compare (or the image thumbnail/name) on the Images screen to open an interactive slider that overlays the original image against its WebP version — drag the handle (or use your keyboard) to reveal one over the other.
Alongside the visual slider, the comparison panel shows the hard numbers: original file size, WebP file size, total savings (percentage and bytes), and image dimensions. Comparison data is loaded on demand when you open the tool, so it adds no overhead to normal browsing. The view is completely read-only — it never alters your files.
Keep your WebP optimization working seamlessly when your media library lives in the cloud. The Pro add-on integrates with WP Offload Media, covering Amazon S3, Cloudflare R2, DigitalOcean Spaces, and Google Cloud Storage.
When an image is converted, its generated WebP file (and all thumbnail sizes) is automatically uploaded to your bucket alongside the original, and your site serves the remote WebP version — including in responsive srcset markup — for faster delivery through your CDN. The integration also works in reverse: it can convert images whose originals have already been offloaded (and are no longer stored locally), and when you restore an image it cleans up the corresponding remote WebP file. A dedicated Compatibility screen detects your offload setup, shows the active provider, and reports sync status. The whole integration is additive and fault-tolerant — if no offload plugin is present, it simply stays out of the way.
When Auto Convert on Upload is enabled, the plugin hooks wp_generate_attachment_metadata and processes each new JPEG/PNG/GIF:
If conversion fails or the image is over the size limit, the plugin records the reason and, where applicable, shows an admin notice.
The Bulk Convert screen processes the existing library in batches using a background batch processor. The workflow is shown as four steps: Scan → Configure → Convert → Results.
/bulk, /bulk/process, /bulk/status), updating the progress bar and counters.(Pro) Restore all original images — one button reverses every conversion and serves originals again.
(Pro) Image Library — a table listing each image with its original size, WebP size, space saved, and status, plus per-row actions to convert, re-convert, or restore individual images.
imagewebp) or ImageMagick, per the Conversion Engine setting.With Enable WebP Serving on, the plugin filters attachment URLs, thumbnail src, and srcset to return the WebP version when one exists. Original files remain on disk as a fallback. No theme edits are required.
The plugin keeps your original files and records the generated WebP paths, so conversions can be reversed:
For each supported image, the Media Library shows:
The Logs screen lists conversion activity and errors with Level, attachment ID, Image, Message, and Time columns. You can search, select entries, and delete them. Logging is controlled by the Enable System Logs setting.
The plugin creates three custom tables (prefixed with your site’s table prefix):
| Table | Purpose |
|---|---|
{prefix}sdic_images |
Per-image record: attachment ID, original/WebP size, bytes saved, status, timestamp |
{prefix}sdic_logs |
Conversion activity log entries |
{prefix}sdic_queue |
Background queue: attachment ID, status, attempts, timestamps |
It also stores plugin options (prefixed sdic_) and attachment meta (prefixed _sdic_, e.g. WebP path/URL/variants, original size, backup map). On delete, the plugin’s uninstall.php removes these tables, options, transients, and meta.
sdic_debug_logaction($message)Fired only when WP_DEBUG is enabled.
| Hook | Type | Parameters | Purpose |
|---|---|---|---|
sdic_is_pro |
filter | (bool) |
Return true to signal the Pro add-on is active. |
sdic_settings_defaults |
filter | (array $defaults) |
Add/modify default settings keys. |
sdic_pre_save_settings |
filter | (array $settings, array $payload) |
Adjust settings before they are saved. |
sdic_register_rest_routes |
action | ($namespace, $controller) |
Register additional REST routes under the plugin namespace. |
sdic_batch_init |
action | — | Fired when the bulk batch processor initializes. |
The Pro add-on also uses WordPress’s core big_image_size_threshold filter for the Large Image Scaling setting.
A command is registered when WP-CLI is available:
wp sdic bulksdic_process_queue_cron — processes the queue (uses a custom one-minute schedule).sdic_daily_optimize_cron — daily scan that enqueues unconverted images (when Auto Convert is on).For issues not covered above: functionality not clearly defined in the plugin files — review the Logs screen (Pro) and the /health endpoint output.
manage_options capability and use WordPress nonces.SPINX Digital Image Converter is developed by SPINX Digital. For support, include the details listed in the FAQ.
Email: dev@spinxdigital.com