Add up to 30 JPG images (up to 50 MB each) and recompress them with MozJPEG at a quality from 10 to 100 (default 85). EXIF data and the color profile are kept by default, or you can strip them, and any photo that wouldn't get smaller is returned unchanged. A live estimate shows the new size before you download, and everything runs in your browser.
Compress JPG images in your browser
This JPG compressor makes JPEG files smaller while keeping them looking the same, and your photos are never uploaded.
JPEG is the most widely used format for photos. Its lossy compression, standardized in 1992, splits the image into 8 × 8 pixel blocks, converts each block with the discrete cosine transform (DCT), and discards fine detail the eye is less sensitive to. That suits photos and works poorly for graphics and text.
Many JPEGs are larger than they need to be. Cameras and phones save at high quality, and editing software often exports with generic settings. Recompressing at quality 75 to 85 with MozJPEG, an encoder tuned for smaller files at the same visual quality, frequently cuts the size a lot. The quality slider lets you find the balance, and the preview shows the result.
When to compress JPEG files
Compress JPEGs to speed up page loads, fit email attachment limits, save mobile data, or prepare photos for the web. Phone and camera photos are often several megabytes, far more than a web page needs.
Typical jobs are blog images, product photos for online stores, email attachments and social media uploads. JPEG works best for photos: landscapes, portraits and product shots with natural color variation. For logos, text, screenshots or transparency, use PNG, WebP or AVIF. For a whole photo library, smaller files also mean less storage and faster backups, and on slow mobile connections they load much sooner.
How JPEG compression works
The DCT turns each 8 × 8 block into frequency coefficients. Low frequencies describe smooth areas, and high frequencies describe fine detail and edges. Quantization then rounds the high-frequency coefficients more coarsely, and the quality setting controls how much. This is where most of the size reduction comes from, and the discarded detail can't be recovered.
JPEG also stores color at lower resolution than brightness, because the eye notices brightness detail more. The common 4:2:0 subsampling, which this tool uses, keeps brightness at full resolution and halves color resolution in both directions. Finally, Huffman coding packs the data losslessly, and MozJPEG optimizes those tables for each image.
Compression artifacts show up as visible 8 × 8 blocks in flat areas, halos around sharp edges (ringing) and color bleeding between areas. They get stronger at lower quality and after repeated saves.
This tool writes baseline (non-progressive) JPEGs, which every program and device can open. Compared with modern formats, JPEG files are usually larger than WebP or AVIF at similar quality, but JPEG works everywhere. To convert photos to those formats, use JPG to WebP or JPG to AVIF.
FAQ: JPG Compressor
Does this upload my images?
No. Compression happens in your browser, and your photos never leave your device.
What quality setting should I use?
For web photos, 75 to 85 gives good results, and 80 is a reliable starting point. Use 90 or more for print or archives, and 60 to 70 for thumbnails where fine detail matters less.
Will repeated compression degrade quality?
Yes. Each lossy save adds a little more loss, so recompress from the best version you have, ideally the original camera file, rather than from an already shrunk copy. If recompressing doesn't make a file smaller, the tool keeps the original.
What is progressive JPEG?
A progressive JPEG loads in several passes: a blurry version of the whole image first, then more detail. It can make a page feel faster. This tool creates baseline JPEGs, which load top to bottom and open in every program.
Can I compress multiple JPEG files at once?
Yes. Add up to 30 JPG files and compress them with the same settings, then download them one by one or as a ZIP.
What is chroma subsampling?
It stores color at lower resolution than brightness, because the eye notices brightness detail more. With the common 4:2:0 scheme, used here, color is stored at half the resolution horizontally and vertically, a quarter of the original color data, with little visible effect.
Does compression affect EXIF metadata?
By default the compressor keeps the EXIF data (camera, date, lens settings and GPS location) and the color profile, and resets the orientation tag because the pixels are saved upright. Turn the option off to remove all metadata, or use the metadata cleaner to strip it from a JPG without recompressing.
What are JPEG artifacts?
Visible defects from lossy compression: 8 × 8 blocks in flat areas, halos around sharp edges, and colors bleeding into neighboring areas. They grow at lower quality settings and with repeated saves.
Is there a quality where JPEG becomes lossless?
No. Standard JPEG is always lossy, even at quality 100, because of rounding and color subsampling. For lossless storage, use PNG or lossless WebP. At quality 95 and above, artifacts are hard to see in most photos.
Why do some JPEGs compress better than others?
It depends on the content and on how the file was saved. Photos with soft edges and moderate detail compress well, while fine textures, noise, sharp edges and text don't. Images that were already heavily compressed have little left to save.