Skyneuron Image Optimizer

Skyneuron Image Optimizer — a professional bulk image optimization module for OpenCart 2.3–4 that uses PHP ImageMagick to compress and convert product images directly from the admin panel.

How it works
The module scans product, category, and manufacturer images, adds them to a queue, then processes them in batches via AJAX requests. Each request is independent — the browser can be closed and optimization will continue on the server. Cursor-based pagination instead of OFFSET ensures stable performance even on stores with 1,000,000+ images.

Processing modes
— In-place optimization — JPEG: metadata stripping, progressive encoding, Huffman table optimization. PNG: lossless recompression and metadata stripping
— PNG → JPG conversion — automatic alpha channel flattening onto a configurable background color, database path updates, automatic deletion of the original PNG after successful conversion
— Dry Run — estimates savings without modifying any files. Shows how much space will be freed before committing to a real run

Safety and reliability
— gzip-compressed backup of originals before any file modification
— Automatic restore from backup if the processed output is corrupted or larger than the original
— Transactional database updates — on conversion, all affected tables are updated within a single transaction; partial updates are impossible
— Automatic .htaccess protection of the backup directory — web access to backup files is blocked on install
— Advisory lock via flock() — prevents two optimization processes from running simultaneously

Smart processing
— Already-optimized file detection via MD5 hash — if a file has not changed since the last run, it is skipped automatically
— Duplicate detection — after scanning, shows groups of physically identical files and how much disk space is wasted
— Three queue priority modes: scan order, largest files first, smallest files first

Ease of use
— Pause / Continue — cursor is saved to localStorage; optimization can be resumed even after a full page reload
— Estimated time remaining — forecast based on the rolling average of the last 5 batch durations
— Browser tab progress — the tab title shows the completion percentage while optimization is running
— Automatic retry — on timeout (90 seconds) the client automatically retries the request up to 3 times
— Format filter during scanning — All / PNG only / JPG only
— Top largest unoptimized files — shows where the biggest savings opportunity is immediately after scanning

Statistics and analytics
— Optimization session history — start and finish time, duration, images processed, errors, bytes saved
— Top categories by bytes saved with progress bars
— Queue statistics — format breakdown, images with transparency, missing files, total size
— Built-in log viewer with copy support

Technical specifications
— Supported formats: JPEG, PNG
— O(log N) cursor pagination — no performance degradation on large catalogs
— Scans categories and manufacturers alongside products
— Settings: JPEG quality, progressive encoding, metadata stripping, Huffman optimization, maximum dimensions (width/height), batch size, delay between batches
— Logging with three levels: INFO, WARNING, ERROR

Compatible with: OpenCart 2.3 – 4
Requires: PHP ImageMagick extension