# Compress Images in WordPress > Bulk-compress your media library with lossy or lossless WordPress image compression. Set your own quality %, compress on upload, keep pages fast. - Canonical URL: - Markdown URL: Category: Speed feature (Pro) Trim image size, not the sharpness. ThumbPress's image compression shrinks your files and speeds up page loads for better performance. ## How Compression Works 1. **Choose a mode** — lossless strips metadata and redundant data without touching a pixel; lossy discards fine detail the eye rarely notices for much smaller files. 2. **Set a quality level** — pick the compression percentage yourself rather than accepting a fixed preset. 3. **Run it** — compress the existing library in bulk, compress a single attachment, or switch on compress-on-upload so new images are handled automatically. ## What You Get - Typical savings of 40-70% on photo-heavy libraries saved with default camera or export settings - Every registered thumbnail size is compressed alongside the original, not just the full-size file - Bulk runs process in batches through Action Scheduler with live progress and a cancel button, so large libraries never hit a PHP execution limit - Runs entirely on your own server using the image libraries PHP already has — no third-party API, no per-image credits, no monthly quota - The dashboard reports exactly how many bytes each run reclaimed ## Frequently Asked Questions ### Does ThumbPress keep a copy of original images? No. Compressed images replace the original files. ### Can I control how much compression is applied? Yes. You can choose different compression levels depending on your needs. ### Does ThumbPress compress existing images in the media library? Yes. You can apply compression to images that are already uploaded. ### Is compression reversible in ThumbPress? No. Once an image is compressed, the original version is not restored automatically. ### What's the difference between lossy and lossless compression? Lossless compression strips metadata and redundant data without touching a single pixel, so the image is byte-for-byte identical to look at. Lossy compression discards fine detail the eye rarely notices and gets you much smaller files. Lossy is the right default for photos; lossless suits logos, screenshots and line art. ### Does compression also cover my thumbnails? Yes. Every registered image size generated from an upload is compressed alongside the original, so a single run shrinks the whole set rather than just the full-size file. ### Are my images uploaded to an external service? No. Compression runs entirely on your own server using the image libraries PHP already has installed. Nothing is sent to a third-party API, so there are no per-image credits, no monthly quotas and no privacy trade-off. ### Will compressing a large library time out? No. Bulk compression runs in batches through Action Scheduler in the background, with live progress and a cancel button, so even libraries with tens of thousands of images finish without hitting a PHP execution limit. ### Can new uploads be compressed automatically? Yes. Switch on compress-on-upload and every new image is compressed as it enters the media library, so you never have to run a bulk pass again for new content. ### How much space will I actually save? It depends on your source images and the quality level you pick, but photo-heavy libraries saved with default camera or export settings commonly drop 40-70% in size. The dashboard reports exactly how many bytes each run reclaimed. ## Ready to Compress? Get started today. Love it or get a refund within 30 days. ## About ThumbPress ThumbPress is a WordPress plugin for image optimization and thumbnail management, built by Codexpert. It runs on your own server: compression, WebP/AVIF conversion and cleanup all happen locally, with no third-party image API and no per-image credits. - All features: - Pricing: - Documentation: - Blog: - Support: - WordPress.org listing: