Thumbnail Manager

FAQ

Can I use Thumbnail Manager with Media Optimizer?

The Media Optimizer tab introduces the free companion, shows its installation and compatibility state, and links to the standard WordPress screens to review installation or activation. Opening the tab does not install, activate or start processing media.

With compatible versions active, Thumbnail Manager prevents Media Optimizer from automatically processing files during thumbnail transactions. After a completed Repair or Force regeneration job, open its saved result and choose “Create WebP/AVIF for completed thumbnails”. Media Optimizer previews the exact successful generated files and requires a separate Run action. This handoff excludes full-size originals and unrelated thumbnail sizes, even when original optimization is enabled in Media Optimizer.

An unfinished Thumbnail Manager job blocks Media Optimizer writes. Complete or cancel the job before optimizing. Expired results, changed files and missing evidence require a new check; they never expand into a whole-library run. Older active Media Optimizer versions must be updated before Thumbnail Manager media operations can run together. Prune itself continues to preserve optimizer sidecars. After a completed Prune, choose “Review leftover WebP/AVIF sidecars” in its saved result. Media Optimizer prepares a separate preview and approval for each page of up to 100 deleted thumbnail files, then deletes at most eight verified sidecars per explicit batch. Only unchanged sidecars with recorded Optimizer ownership can qualify; legacy, referenced, replaced or unverifiable files remain preserved. Opening the preview never approves or deletes files.

Source optimization and restore attempts in Media Optimizer also mark older thumbnail observations and Recommendations for a fresh check. This is conservative: a partial or no-change attempt can still trigger the warning. Saved outcomes are retained; no thumbnails are regenerated automatically. Older results without a source revision snapshot disclose that freshness cannot be confirmed.

Can I regenerate thumbnails after changing image sizes?

Yes. Check and repair missing thumbnails first inspects the selected images and the sizes currently enabled in Thumbnail Sizes. Review the results, then choose Repair missing thumbnails. Repair uses the current full image, honors edits, and preserves existing thumbnails and unrelated metadata. Sizes that cannot be made without enlarging the source are not required. Force Regenerate rebuilds the selected attachments more comprehensively from an available original image source and follows the enabled-size policy.

Regenerate can process all media, current-year images, one uploads folder, or specific image attachments. Choose the narrowest useful scope before starting a large job. Under Thumbnail sizes for this job, leave All enabled sizes selected for the default behavior, or choose one or more enabled sizes. The job selection does not change future-upload settings. Images and sizes outside the selected scope are preserved; sizes disabled or unregistered later are not recreated.

How do I check and repair selected images?

In Media > Library, use Check thumbnails on an image, or select images in list view and choose the Check thumbnails bulk action. In Tools > Thumbnails > Regenerate, you can also choose Selected images > Choose images and use the familiar Media Library search and filters. Select up to 500 images at a time; folder and broader scopes run in bounded batches.

Choose Check thumbnails, review the per-image and per-size results, then explicitly choose Repair missing thumbnails. Navigation and checking do not modify media. Repair derives the selection from the saved check and rechecks current files and enabled sizes before generating anything. Recent jobs lets you reopen saved check and repair results.

Checks cover currently enabled registered thumbnail sizes and local upload files. A present file is not a full corruption audit, and the report does not verify frontend pages, external references or CDN copies. Disabled and historical unregistered sizes are preserved and are not recreated. Missing original/full files, missing or malformed complete attachment metadata, unsupported formats and unsafe paths require the suggested manual action; the plugin cannot reconstruct a lost original. An occupied, unreferenced destination is preserved rather than overwritten.

Jobs continue only while the administration page sends batches. After a network interruption or page reload, return to the plugin page to resume the saved active job. Stopping keeps completed work and its audit record; in-flight transactions may need recovery before stopping finishes. After expiry or after resolving a blocked source/storage issue, run a new check. Result retention is temporary, not a permanent media audit.

What evidence do Recommendations show?

Recommendations distinguish protected-size policies, recorded attachment metadata and size-name hints found in post content. Content examples link to related posts when accessible so you can check the reference. A size-name hint such as an image class or a stored size setting does not prove that a particular attachment or file is in use. Examples are limited to five posts per size and are not an exhaustive reference list.

Review the reported scan coverage and confidence. Theme templates, custom code, external content, page-builder storage outside the scanned post content and frontend/CDN delivery are not fully inspected. Missing evidence is not proof that a size can be disabled or deleted.

What do the image, thumbnail and storage counts mean?

Recommendation statistics separate scanned image attachments, generated size entries recorded in metadata and local files actually checked. The checked-byte total counts each verified canonical file path once, even when metadata references it more than once. Different hard-link paths are not identified as the same physical storage allocation.

These observations cover registered-size metadata during the scan, not all files under uploads or a live filesystem snapshot. Missing files, unreadable files and entries that cannot be verified are reported separately. Per-size savings and Prune candidate bytes are estimates; recorded bytes freed describe the completed deletion work. Review the displayed coverage and limitations before treating a figure as a whole-library total.

How can I retry unsuccessful items?

Open a finished job from Recent jobs, filter its unsuccessful items and review the reason and suggested action. Resolve source, permission or storage issues, select eligible items and choose Retry selected items in a new job. The new job rechecks current conditions and leaves completed items and the original result unchanged. Some skipped items, such as sizes not needed for the source dimensions, require no action.

Resume continues a valid active job; retry starts a separate job from selected unsuccessful items in an available finished or stopped result. Expired results and items with pending media-recovery evidence cannot start a fresh retry. A Prune retry prepares a new preview and requires fresh approval before deletion.

Can I reopen or export job results?

Use Recent jobs to reopen checks, repairs, regeneration, Recommendations and Prune results. Viewing a saved result does not run the job. Results show the selected scope, outcome counts, item details where available, error reasons, suggested next steps, timestamps and the saved retention deadline. Finished or stopped results are normally retained for seven days; retention is temporary, not a permanent audit archive.

Choose Download JSON report from the result view to keep a basic report or send it to support. Export reads the same saved result pages used by the interface. An active job can change during export, so use a finished job for a stable report. Partial, expired or older results may have limited details; their limitations are disclosed. If the saved data is no longer available, run a new check or scan for current evidence.

Can it clean unused generated thumbnails?

Yes. Prune Files first builds a manifest for review. Nothing is deleted until the scan finishes and an administrator explicitly approves that manifest.

Will it delete original images?

No. Original full-size uploads are protected. Cleanup candidates must also pass path, ownership, source, and manifest checks.

Can I scan several upload folders?

Yes, in Prune Files. Search for and select multiple years or months. Selecting an entire year automatically covers its month folders.

Is it suitable for a large Media Library?

Yes. Recommendations, regeneration, scanning, manifest creation, and deletion use persistent jobs and bounded batches that can resume after interruption.

What happens if I close the page during a job?

The job state remains in the database. Reload the admin page to resume it. Cancelling stops future batches while retaining an audit record.

Can Prune Files delete old disk-only thumbnails?

Only when they can be verified conservatively. You can opt in to verified legacy thumbnails for currently disabled sizes, and separately opt in to verified historical thumbnails from sizes that are no longer registered. Unmapped filename matches, ambiguous files, sidecars, edit/backup-like siblings, and other files without sufficient ownership evidence are preserved by default.

Is it safe for WooCommerce sites?

The plugin recognizes WooCommerce-related sizes in Recommendations, but storefront requirements vary. Verify the sizes used by your store before disabling or pruning them.

Does disabling a size unregister it from a theme or plugin?

No. It changes which registered sizes WordPress generates for future uploads and regeneration. The original registration remains in place.

What data remains after deactivation or plugin deletion?

Deactivation clears Thumbnail Manager’s scheduled cleanup task but retains settings, job history, recovery evidence, and media-reference data. Deleting the plugin files intentionally retains the same database state and does not delete attachment metadata, uploads, generated thumbnails, or recovery files. This retained state may be reused after reinstall, subject to the plugin’s normal expiry, ownership, and authorization checks. Remove retained database data separately only if your site’s privacy and recovery requirements allow it.