Compress JPG

Compress JPG is a focused tool for one job: taking a JPEG photo and producing a smaller JPEG photo. Where the general Compress Image tool spreads its attention across five formats, this one concentrates on the JPEG standard and its quirks, then exposes a single quality slider plus a metadata choice so you can tune the exact tradeoff between appearance and file weight.

The everyday scenarios are instantly familiar. A blog post needs images under a platform upload limit. A photo album going out by email keeps bouncing off an attachment ceiling. A marketplace listing requires JPGs under a specific megabyte count, or a storage folder simply needs to shrink by half. In all of these the photo stays a photo - nothing is cropped, resized or re-saved as a new format - which keeps the workflow predictable and the result compatible with every system that already reads JPEG.

The quality slider is the tool's center of gravity. It sets how much detail the encoder discards when it rebuilds the file, and because JPEG is a lossy format, every value on the scale involves some tradeoff. The relationship is well understood, though: values in the 70-80 range are the standard landing zone for web use, delivering files that are often 60-80 percent smaller than the source while remaining sharp on normal displays. Lower values buy extra space at the cost of visible artifacts, and pushing toward 100 protects detail at the cost of large files that defeat the purpose of compressing at all.

JPEG files also carry metadata that has nothing to do with the picture: camera settings, dates, GPS coordinates, a color profile and an embedded preview thumbnail. The tool lets you decide whether that metadata survives into the output or is stripped. Keeping it is useful for archival records, while stripping it reduces size at zero visual cost and removes location data before a photo is shared. It is one of the few compression decisions that costs you nothing either way you choose.

Everything runs locally through the browser canvas, so the photo never leaves your device: no upload endpoint exists. That local model is what makes the tool safe for headshots, client previews and other semi-private material. Before you start, remember the boundaries: input is JPG or JPEG only, the limit is roughly 25 MB per file, and compression reduces file size rather than pixel dimensions - a 4000-pixel-wide photo stays 4000 pixels wide no matter how far you drop the quality slider.

Reading the quality slider honestly requires understanding where the size actually goes. When the browser re-encodes a JPEG, it walks a well-known sequence: the image is converted from RGB into a luminance-plus-color representation, the color channels are usually stored at reduced resolution, the frame is split into 8 x 8 pixel blocks, and each block is transformed into frequency coefficients. The quality value then picks a quantization table that decides how coarsely those coefficients are stored.

The practical effect is that compression is applied to detail the eye tolerates before it touches structure the eye depends on. Brightness differences survive better than small color differences, and gradual tonal changes survive better than sharp high-frequency texture. That ordering is why a moderately compressed photo of a landscape still looks clean while the same setting can make a graph or a screenshot with fine text look soft and noisy.

Professionals rarely pick a quality value by feel. They match it to the destination: how large the image will be displayed, what kind of content it holds, and how much bandwidth the audience has. A hero photo for a phone-viewing audience does not need the same fidelity as a print proof, and a photograph of a face does not need the same margins as one containing fine text or tiny logos.

The safest method is to work downward from a known-good value rather than upward from a small one. Compress at 80, inspect the output at 100 percent zoom, and only move lower when the visible result is genuinely acceptable at the size it will actually be displayed. Sizes on screen are forgiving; the same image opened in an editor at full resolution is not, so always judge with the real destination in mind.

When a compressed JPG looks wrong, the artifact itself usually names the cause. Blocking - the coarse square grid that appears in smooth areas - signals a quality value so low that entire 8 x 8 blocks collapsed to a single tone. Banding, the staircase of visible steps across a gradient sky or backdrop, is quantization pulling a continuous ramp down to a handful of distinct levels. Color smearing along sharp edges comes from chroma subsampling interacting with bright saturated pixels.

The useful response is to fix the cause rather than fight the symptom. Raising quality addresses blocking and banding directly. For color smearing, the more robust fix is sometimes to convert the gradient or graphic content to a format with finer color handling, or to preserve higher quality on that file specifically. Recognizing the artifact is the difference between guessing and correcting.

• Blocking: raise the quality value, or avoid flat mid-tone areas compressed at low settings.
• Banding: raise quality, or add a whisper of noise in the source to break up the staircase.
• Edge color bleed: prefer higher quality on saturated red and blue detail, or use a format without aggressive subsampling.
• Overall softness: the source may already have been compressed before - go back to the original, not the damaged copy.

A single JPG can hold several independent metadata blocks alongside the pixels. EXIF stores the camera make and model, exposure settings, date and, on phones, the GPS position where the shot was taken. An ICC profile records the color space so displays render the tones as intended. A thumbnail preserves a small preview copy, and XMP or IPTC blocks can hold captions, copyright and workflow notes.

Stripping all of it is the aggressive default for anything going public: the file loses its location data, its device fingerprint and a pile of preview bytes, and the picture itself is untouched. Keeping it is the right call when the file is an archive or when downstream software needs the capture record. The tool's strength here is that the choice is explicit instead of hidden, so the metadata that survives is metadata you intended to keep.

• For personal archives destined for an editor, keeping EXIF preserves the settings used on location.
• For anything emailed, published or sent to a client, stripping removes GPS and device identity in one step.
• The ICC profile is the one block whose removal can slightly change appearance - keep a profiled original when color fidelity matters.
• Stripping never changes pixel content; it only removes the invisible sidecar records.

JPEG is a deliverable format, not a working format. The professional habit is to keep a master - a lossless original, or at least the highest-quality export the source can produce - and to compress only the copies that ship. Because every compression pass is a generation, the master exists so a damaged deliverable can be rebuilt without stacking further losses.

When you operate that way, compression becomes a one-way project step rather than a recurring tax. A photo flows from the camera into an editor, the finished edit exports once at high quality, and only that finished file is compressed for delivery. Following that order means every copy on the page is one generation old at most, and the artifacts that plague twice-saved files simply never appear.

• Never compress, edit, then compress again in a loop - edit the original and compress the finished file once.
• Name deliverables to mark the compression stage so nobody re-compresses an already-optimized file by accident.
• When the same photo must appear at several sizes, resize each variant and compress each variant separately.
• Run the whole batch with identical settings so a folder reads as consistent rather than a mix of makers.