EPUB Image Optimizer

Drop an EPUB here or choose a file to create an optimized copy. Your original file is never changed.

JPEG quality

78%

Lower values save more space. Existing PNGs stay PNGs for reader compatibility.

Maximum image edge

Large images are scaled down before the EPUB is rebuilt.

Ready to optimize.

Current run

Images optimized 0

Images kept original 0

Original size -

Optimized size -

Saved -

Runs locally in your browser; EPUB files are not uploaded.
Keeps the EPUB mimetype entry uncompressed for standards compliance.
Compares every image and keeps the original if optimization would make it larger.

Best results come from EPUBs with oversized JPG or PNG artwork. DRM-protected books and unsupported image formats are copied through unchanged.