Effortless Simple Image Optimiser hooks directly into the WordPress Media Library upload pipeline and compresses, resizes and (optionally) converts images the moment they are uploaded — all using the built-in PHP GD extension. It also provides admin tools under Settings Image Optimiser to process images already in your Media Library, find and remove duplicate files, regenerate thumbnails, and manage the original-file backups the plugin keeps automatically.

Upload-time optimisation

JPEG compression — re-encodes JPEGs at a configurable quality level (default: 82). GD strips EXIF metadata automatically, further reducing file size.
PNG compression — applies lossless GD compression to PNG files.
PNG JPEG conversion — converts opaque (non-transparent) PNGs to JPEG for significant space savings. Transparent PNGs are always kept as PNG.
Image resizing — scales down images that exceed a configurable maximum width or height while maintaining the original aspect ratio.
WebP generation — optionally saves a .webp sidecar file alongside every optimised image (requires GD compiled with WebP support).
Automatic original backup — before any image is optimised, the plugin saves an untouched copy of the original file. This happens every time, with no setting to turn it off — see the Originals tab below to restore or discard these backups.
Graceful degradation — if GD is not available the plugin skips processing and logs a notice; uploads are never blocked.

Bulk Optimise tab

Processes every image already in your Media Library using your current settings, one image at a time. Shows total / optimised / pending counts, offers a “re-optimise all” option to force reprocessing, and includes a ghost-attachment scanner (finds and lets you delete Media Library records whose file no longer exists on disk). On a large library, both counting and processing automatically continue across as many requests as needed rather than stopping partway through.

Regenerate Thumbnails tab

Regenerates every registered thumbnail size for existing Media Library images — useful after a theme changes its image sizes or adds new crop dimensions. Also scales across a library of any size the same way as Bulk Optimise.

Find Duplicates tab

Scans the Media Library for exact duplicate image files (compared by file hash). The oldest copy (lowest attachment ID) is always kept; the “Fix all duplicates” action updates every reference to a duplicate in post content, post meta and featured images to point at the kept copy, then deletes the redundant files.

Originals tab

Shows how many original backups are stored and how much disk space they use. Restore all originals copies every stored original back over its optimised version, removes any WebP sidecar, and regenerates thumbnails. Discard all originals permanently deletes the stored backups to free disk space — do this only once you are satisfied with the optimised results, since restoring is no longer possible afterwards for a discarded image.

Settings

Navigate to Settings Image Optimiser to configure:

Enable / disable automatic optimisation on upload
JPEG quality (1–100, default 82)
Enable PNG JPEG conversion
Enable WebP sidecar generation + WebP quality
Enable / disable resizing
Maximum width in pixels (default 1920)
Maximum height in pixels (default 1920)

Requirements

PHP 7.4 or higher
PHP GD extension (enabled on virtually all shared hosting)
WordPress 5.9 or higher

EffortLess Simple Image Optimiser