Compress JPG

How it works

1. 1Open the tool with JPEG selected as the output format.
2. 2Upload one image. The page shows a preview and the image size before you compress.
3. 3Set a quality from 1 to 100. The default is 75. Or enter a target file size in KB instead.
4. 4Press the button to compress the image, then check the result panel for the new size and the percent saved.
5. 5Download the file and keep your original.

Example output

Original JPG, 1600 x 1200 px, 538 KB

Compressed JPG, quality 75, 120 KB

How to compress a JPG

Upload your JPG, leave the output format on JPEG, and choose a quality. The default quality is 75, which is a place to start. Press the button and the result panel shows the original size, the new size and how much smaller the file is.

The page opens with JPEG selected, so you do not need to change anything for a basic compress. If you want a different output, you can switch to PNG, WebP or "Same as the original". Download the result when you are happy with it.

• Start at the default quality of 75.
• Check the result panel before you replace your original file.

What JPG compression does

JPG compression re-encodes the picture at a lower quality. The encoder used is mozjpeg, and the result is a progressive JPEG. The pixel size of the picture never changes, so a 1600 x 1200 photo stays 1600 x 1200.

MDN calls JPEG the most widely used lossy compression format for still images. Photographs and other continuous-tone images can usually tolerate lossy compression, because the discarded detail is harder to see. Compression is still lossy. Detail that is removed cannot be brought back, and saving a JPEG again loses a little more, so keep the original file.

Choosing the quality

Quality runs from 1 to 100, and the default is 75. Lower numbers make a smaller file with more visible loss. Higher numbers keep more detail but leave a larger file.

In our test, a 1600 x 1200 photo saved as JPEG at quality 92 was 538 KB. At quality 50 it became 38 KB, at quality 75 it became 120 KB, and at quality 85 it became 227 KB. Results vary by picture, so compare a few settings on your own image before you choose one.

• Quality 75 is the default and a good place to start.
• If the result looks rough, raise the quality and compress again from your original.

Compress a JPG to a target size in KB

You can enter a target file size in KB instead of a quality. The tool searches for a quality that gets the file close to your target. The search uses at most 7 trial encodes, and the target size must be between 1 and 20480 KB.

In our test, a target of 100 KB gave 99 KB, a target of 200 KB gave 192 KB, and a target of 400 KB gave 387 KB. A target of 5 KB could not be reached: the smallest result was 6.4 KB, and the panel said the target was not reached. The tool never silently relaxes a target. If the search stops early to stay inside the time limit, the panel says so.

When the file does not get smaller

Sometimes the compressed file is not smaller than the original. This happens most often when the JPG was already compressed hard. The result panel says so plainly, and the file is still offered for download.

In our test, a picture saved at quality 40 (57 KB) became 70 KB at quality 75. That result was about 22% larger, and the panel said it was not smaller. At quality 30 the same picture became 21 KB. If the panel warns you, try a lower quality or keep the original.

• A file that is already compressed may not shrink further.
• If the original is already small, the compressor cannot help much.

Compress image files: JPG, PNG and WebP

This page is set up for JPG, but the same compressor also works on PNG and WebP. Choose the output format that suits your file. The compressor does not change the pixel size of your picture in any format.

For PNG, the compressor reduces colours to a palette of at most 256 colours, with dithering. This is lossy. You can also tick "Lossless" for PNG, which keeps all colours and only uses stronger deflate. For WebP, the compression is lossy unless you tick "Lossless". A photograph is usually a poor fit for PNG, so JPEG or WebP is often the better choice.

Why people compress JPG files

Smaller JPG files are easier to upload, email and store. Some forms and websites set a maximum file size, and a compressed JPG may fit under that limit without changing the picture dimensions. The target size setting is meant for that case.

Use the quality setting to balance file size and picture detail for your use. Keep the original so you can compress again with different settings later.

Rotated photos, camera tags and transparent pictures

A photo stored with EXIF orientation is turned upright in the result. In our test, a 1600 x 1200 file marked with orientation 6 came out upright as 1200 x 1600, and its size went from 465 KB to 120 KB at quality 75.

Camera and location tags, such as EXIF and GPS data, are not copied into the result. JPEG does not support an alpha channel, so transparent areas are always filled with the background colour. The default background is white. In our test, a transparent 1024 x 1024 PNG logo of 37 KB became 17 KB as a JPEG at quality 75, with the transparent area filled with white.

Compressing is not the same as making the picture smaller

Compressing a JPG makes the file smaller in bytes. It does not make the picture smaller in pixels. A 1600 x 1200 photo is still 1600 x 1200 after compression. If you need fewer pixels, use the Size setting on the converter pages, such as the PNG to JPG tool. This compressor has no resize setting.

Compression removes some detail from the image data, so check the result at the size you plan to use.

Which files the compressor accepts

The tool accepts PNG, JPG (also .jpeg and .jfif), WebP, AVIF, GIF, BMP and TIFF. It does not accept SVG, PDF, HEIC/HEIF, BigTIFF or camera RAW files. The file type is read from the content, not the file name, so a renamed file is read as what it really is.

The free web tool accepts up to 5 MB per image, and up to 16 MP (4096 x 4096) per image. Signed-in users can upload up to 10 MB per image. Free use allows 30 images per day per visitor. Signed-in users pay 1 credit per image, plus 1 credit for each 5 MB of result after the first 5 MB. The result can be at most 20 MB. If it would be larger, the job fails with an "output too large" message instead of returning a cut-off file.

• The web tool handles one image at a time.
• An animated GIF or WebP keeps its frames when the output is WebP or "Same as the original". With JPEG or PNG output, and for an animated AVIF, only the first frame is used. The GIF compressor page has the GIF settings.

Compress JPG from code

You can compress JPG files through the API. Use the image compress operation, op=image_compress, with format=jpeg for JPG output. Set quality from 1 to 100 or target_kb from 1 to 20480, not both. Other settings include lossless, keep_transparency and background.

Send the raw image bytes as the request body, not JSON or multipart. Set Content-Type to the image type, such as image/jpeg. Authenticate with an Authorization Bearer header or an x-api-key header. The API returns a job ID, and you poll the job until it succeeds or fails. The download link is short-lived. The tool page shows a ready cURL, Node and Python example below the tool. Full details are in the API docs at /docs/#image-compress.

Privacy: what happens to your file

Your image is sent to our server, and it is not processed in the browser. The processing is done by sharp, built on the libvips library. This is ordinary image processing, not artificial intelligence. The uploaded image is used only to make the result and is deleted as soon as the job ends, whether it succeeds or fails.

The result is deleted after 10 minutes in the free web tool. No history is kept, and download links are short-lived. Download your file before the link expires. You must have the right to use any image you upload, as set out in our Acceptable Use Policy.

Questions