Compress JPG
Reduce JPEG file size with a quality slider. See live before/after KB comparison - no server upload.
Drop an image here or click to select
JPG only - up to 50 MB
or paste an image with Ctrl+V / ⌘V
Your image is processed locally. Nothing is uploaded.
How to use Compress JPG
- 1
Upload your JPG
Drop a JPEG file onto the tool or click to select it from your device.
- 2
Set compression quality
Drag the quality slider. 75-85% gives the best size/quality balance for most photos.
- 3
Check the savings badge
The green badge shows how much smaller your file will be. Aim for at least 30% reduction.
- 4
Download the compressed JPG
Click the download button. Your browser saves the smaller JPEG locally - nothing is uploaded.
How JPEG compression works
JPEG breaks your image into 8x8 pixel blocks and discards frequency information that human vision is least sensitive to. Higher frequency data - fine texture, sharp edges, grain - is reduced first. The quality setting controls how aggressively this happens. At 85%, the discarded information is invisible to most people. At 60%, smooth gradients start to show subtle banding and sharp edges become slightly soft.
This means not all images compress equally. A portrait with a blurred background compresses very well - the large smooth areas need little data. A detailed macro photo of fabric or a photo of text compresses poorly - there is high-frequency information everywhere that JPEG cannot discard without visible degradation.
Practical quality settings
For professional photography displayed on a website or portfolio, 85-92% preserves fine detail and colour accuracy while still reducing file size by 30-50% compared to an uncompressed baseline. For e-commerce product images where fast loading matters, 75-80% is a good target. For social media thumbnails or blog post images displayed at small sizes, 65-75% delivers files below 100 KB for most photos while looking fine at screen resolution. Below 60% is appropriate only for low-priority preview images or very large batches where bandwidth is the primary constraint. If you need to hit a specific file size in kilobytes, the resize to KB tool finds the right quality setting automatically.
When to resize before compressing
Compression alone does not change image dimensions. A 4000x3000 pixel photo compressed to 50 KB is still 12 megapixels - browsers still have to decode and scale all those pixels, which is slow and memory-intensive. Resize your photo to the largest size it will ever be displayed before compressing. That combination produces the smallest file and the fastest load time.