Shrink an image by re-encoding it to JPEG or WebP at the quality you choose, optionally resizing it. Everything runs locally and shows how much you saved.
No. Compression uses a canvas in your browser — the image never leaves your device.
WebP is usually smaller at the same visual quality, but check compatibility with where you'll use the image.
Re-encoding an already-optimized or tiny image can add overhead; lower the quality or keep the original in that case.