Compress
Compress JPG Images
Shrink JPEG files to a target size such as 100 KB or 2 MB, or dial in the quality by hand. Compression happens on your own device, so nothing is uploaded and there is no queue to wait in.
Compression
How JPEG compression works
JPEG does not store your photograph pixel by pixel. It divides the image into blocks of 8 by 8 pixels, converts each block into a set of frequency patterns, and then throws away the patterns your eye is least likely to miss — mostly fine, high-frequency detail. The quality setting controls how aggressively that discarding happens.
This matters for two reasons. First, the loss is permanent: the discarded detail is not recoverable by converting back to PNG or by raising the quality later. Second, the damage compounds. Each time a JPEG is opened and saved again it is decoded and re-encoded, and the block boundaries can shift slightly, so a file saved five times looks noticeably worse than one saved once at the same quality. Always compress from the highest-quality original you have rather than from a copy that has already been through the process.
This tool encodes with MozJPEG, the same encoder used by Squoosh. At an identical quality setting it produces a smaller file than a browser's built-in JPEG encoder, because it spends more effort searching for an efficient encoding of the same visual result.
Choosing a quality level
Quality numbers are not a percentage of anything, and they are not comparable between formats. As a rough guide for photographs:
| Quality | What it looks like | Good for |
|---|---|---|
| 95-100 | Indistinguishable from the original, but files barely shrink | Archiving, further editing |
| 85-94 | No visible difference to almost anyone | Print, marketplace listings, portfolios |
| 75-84 | The sweet spot — big savings, no obvious loss | Websites, blogs, social posts |
| 60-74 | Slight softening; faint blocking in skies | Thumbnails, images displayed small |
| Below 60 | Visible blocks and colour banding | Only when a hard size limit forces it |
Photographs tolerate compression well. Screenshots, logos, diagrams and anything containing text do not — JPEG puts faint halos around sharp edges, which is very visible on lettering. For those, use PNG or WebP instead.
Compressing to an exact file size
Real limits are stated in megabytes. YouTube rejects mobile thumbnail uploads over 2 MB. Contact forms cap attachments at 5 MB. A marketplace wants images under 1 MB. None of these translate into a quality number, which is why most compressors leave you dragging a slider and re-checking the file size by hand.
Switch this tool to By target size and type the limit. It repeatedly encodes the image at different quality settings, narrowing in on the highest quality that still fits underneath your number, and normally settles it in six to eight attempts. If the target genuinely cannot be met without destroying the image, it says so rather than handing you something unusable.
When a target is out of reach, the fix is almost always dimensions rather than quality. File size scales with the number of pixels, so halving the width and the height leaves roughly a quarter of the file. Resize the image first, then compress.
Photos from phones stay the right way up
Phone cameras rarely rotate the pixels they capture. Instead they store the image as the sensor saw it and add an orientation tag saying which way up it should be displayed. Tools that ignore that tag hand back a sideways photo — a common and baffling result when compressing images straight from a phone.
This tool reads the orientation and bakes the correct rotation into the output, so what you download is upright everywhere, including in software that ignores the tag.
How to compress JPG Images
- Drop one or more JPG files onto the box above, or click to browse.
- Choose Target size if you need to fit under a specific limit, or Quality if you would rather judge it by eye.
- Compare the before and after preview by dragging the divider.
- Download the compressed files individually, or all together as a ZIP.
Limits worth knowing
Every tool has boundaries. These are this one's, stated plainly so you do not waste time discovering them yourself.
- JPEG is a lossy format. Every save discards some detail permanently, so always compress from your original rather than from an already-compressed copy.
- Very small target sizes on large images will produce visible blocking. The tool will warn you when it cannot reach a target without heavy damage.
- Compressing an image that is already heavily compressed may barely shrink it, or occasionally grow it slightly. The tool keeps the original if the result is larger.