How do I decrease the file size of a JPEG?

Lower the quality setting when you save or export it, and shrink the pixel dimensions if the image is larger than it needs to be. Dropping quality to around 75 percent usually looks identical to the eye while cutting the file to a fraction of its original size. A compressor tool does both in one step.

Does reducing JPG file size lower the quality?

A little, but usually not in a way you can see. JPG is a lossy format, so every save throws away some data. At 70 to 85 percent quality the loss is invisible for most photos. Problems only show up if you push quality very low or re-save the same file many times.

What quality setting should I use for a JPG?

For web and email, 70 to 85 percent is the sweet spot. It keeps the image looking sharp while removing most of the file weight. Save 90 percent or higher only when you need the image for print or heavy editing.

Why does re-saving a JPG make it worse?

Each time you open a JPG and save it again, the format re-compresses the image and discards more detail. Do this enough times and you get blocky artifacts and muddy color. Always edit from the original file rather than a copy you have already saved several times.

How small can I make a JPG?

Very small. A photo that starts at 4 MB can often drop under 200 KB with no visible change, and under 100 KB if you also reduce the pixel dimensions. The right target depends on where the image is going, so match the size to the use.

How to Reduce JPG File Size Without Losing Quality

A JPG gets smaller in two ways: you compress it harder (lower the quality) or you shrink its pixel dimensions. Most oversized JPGs are heavy on both fronts, which is good news, because you have two levers to pull. The trick to reducing JPG file size without losing visible quality is knowing that you almost never need the full-size, maximum-quality version in the first place.

Here is the part most people miss. A JPG saved at 100 percent quality and the same JPG saved at 80 percent usually look identical on a screen. Your eye cannot tell the difference, but the file at 80 percent might be half the size or less. The last few percent of quality costs a huge amount of file weight for detail nobody sees. So the fastest way to make a JPEG picture file smaller is to stop saving at maximum.

The two levers that control JPG size

Quality (compression). JPG throws away image data to save space. A quality slider set to 100 keeps almost everything. Set it to 75 and it discards the fine detail your eye ignores. For photos headed to email, a website, or a form, 70 to 85 percent quality is the range that looks clean while cutting the file dramatically.

Pixel dimensions. A photo straight off a phone might be 4032 by 3024 pixels. That is far more than a website or an email preview will ever display. If the image only needs to show at 1200 pixels wide, resizing it there removes millions of pixels of data and shrinks the file hard. This is often the bigger lever of the two.

Pull both together and the result compounds. Lower the quality a bit, cut the dimensions to what you actually need, and a 4 MB photo can land under 300 KB while still looking sharp.

How to reduce JPG file size on Windows

The built-in Photos app can resize an image, which handles the dimensions lever.

Right-click the JPG and choose Open with > Photos.
Click the three-dot menu in the top right and choose Resize image (older versions call it Resize).
Pick a smaller preset, or choose Define custom dimensions and enter a width like 1200 pixels.
Set the quality slider if one appears, then click Save resized copy.

This keeps your original untouched and writes a smaller copy. For finer control over the quality setting, the compressor tool below does a better job.

How to reduce JPG file size on a Mac

Preview handles both levers, and it is already on every Mac.

To shrink the dimensions:

Open the JPG in Preview.
Go to Tools > Adjust Size.
Enter a smaller width (say 1200 pixels) with Scale proportionally checked so the height follows automatically.
Click OK.

To lower the quality when you save:

Go to File > Export.
Make sure the format is set to JPEG.
Drag the Quality slider left. Watch the estimated file size update as you drag.
Click Save.

Exporting to a new file, rather than overwriting the original, is the safe move. That way you keep the clean master and only compress the copy you are sending out.

A warning about re-saving

JPG is lossy, and the damage adds up. Every time you open a JPG, make a change, and save it again as JPG, the format re-compresses and drops a little more detail. Do that ten times and you get visible blocking and smeared color. So always start from your original file when you need a new size, rather than compressing a copy that has already been compressed several times. One clean pass from the master beats five passes on a tired copy.

The fast way: use the compressor tool

Doing this by hand for one image is fine. For several images, or when you need to hit a specific target size, use our free JPG Compressor. It runs in your browser, so nothing uploads to a server, and it gives you a quality slider plus a live preview of the result and the new file size. Drag the slider until the size drops where you want it and the image still looks right, then download.

It is the reliable way to compress JPEG file size when you have a ceiling to meet. If you specifically need to fit under a hard cap like 100 KB, our guide on making a JPG under 100KB walks through the exact combination of settings. And if your problem is mostly that the image is too big in dimensions rather than too heavy in quality, see how to resize a JPG without wrecking the quality.

Practical target sizes

Match the size to where the image is going:

Email attachment: aim for 200 KB to 500 KB per photo. Anything under 1 MB sends fast and displays cleanly.
Website or blog image: 100 KB to 300 KB is plenty for a large photo at 1200 to 1600 pixels wide.
Profile picture or thumbnail: under 100 KB, often under 50 KB, since it displays small anyway.
Form or portal upload: check the stated limit and aim just under it.

Start with quality at 80 percent, resize to the width you actually need, and check the result. If it is still too big, drop the quality to 70 and resize a little smaller. Those two moves cover almost every case, and your image will still look like the original to anyone looking at it.