画像圧縮

Compress image files without uploading them

This page lets you compress image files right in your browser. Pick a photo, decide how small it needs to be, and download the result. Nothing goes to a server, which is also why it starts instantly: there's no upload bar to sit through, even with a 15 MB photo from a new phone.

Compression isn't the same as resizing. It re-encodes the picture so it takes fewer bytes, while the width and height in pixels stay exactly as they were. If a form also says "maximum 1000 × 1000 pixels", you'll need the image resizer as well.

How to compress an image

Each photo takes a second or two. You can drop up to 20 images at a time.

1. 1

   画像をアップロード

   JPEG、PNG、WEBP、HEICまたは対応画像をアップロードエリアにドロップするか、複数を一度に選択。

2. 2

   画質レベルを選択

   画質スライダーを動かす（デフォルト80%）。低画質はファイルが小さくなり、アーティファクトが目立ちます。

3. 3

   または目標ファイルサイズを設定

   KBで目標サイズを入力すると、画質が自動調整されそのサイズに近づきます。

4. 4

   圧縮してダウンロード

   画像を圧縮を押し、処理完了を待ち、前後を比較してから小さなファイルをダウンロード。

Compress image to 20KB, 50KB, 100KB or 200KB

Online application forms often set a hard limit. Many Indian recruitment portals, including SSC, IBPS and several state commissions, ask for a photo between 20 KB and 50 KB and a signature between 10 KB and 20 KB. University admissions, visa and passport sites are usually more generous, often 100 KB to 200 KB. Limits change from one notification to the next, so check the one you're applying under.

Type the number into Target file size and the tool keeps lowering the quality until the file fits. Two things decide whether it can get there:

• Pixel count. A target size only lowers quality; it never touches the dimensions. A 4000 × 3000 phone photo won't reach 20 KB at any quality that still looks like a person. Shrink it to roughly 400 × 500 pixels first and 20 KB becomes easy.
• Format. JPEG and WEBP hit small targets well. PNG is reduced by trimming its color palette, which suits logos and screenshots but rarely gets a photo under 50 KB.

Treat these as rough guides for ordinary JPEG photos. A busy scene full of fine texture, like grass, gravel or patterned fabric, needs more bytes than a plain portrait against a white wall.

Which quality setting should you pick?

The slider runs from 10 to 90 and starts at 80. Above 75 most people can't tell the difference on screen, and the file is often half the size of the camera original.

After processing you get a before-and-after slider. Drag it across faces and text, because that's where compression shows first. If it looks rough, nudge the quality up and apply again without re-uploading.

How each format gets compressed

JPEG

JPEG photos are re-encoded with MozJPEG, an encoder built to save extra bytes at the same visual quality. Phones store photos at a very high setting, so the first pass typically removes 40–70% of the file without any visible change.

PNG

PNG has no quality dial of its own. Instead the tool reduces the image to a palette of roughly 40 to 245 colors (fewer as you lower the slider), smooths the steps with dithering and repacks the file with OxiPNG. Screenshots, logos and diagrams often shrink by 60–80% and keep their transparency. Photos saved as PNG shrink far less, so converting PNG to JPG is usually the better choice for them.

WEBP and AVIF

Both formats are already efficient, so expect smaller gains, often 10–30%. They're still worth a pass when you're trimming a web page and every kilobyte counts.

HEIC from iPhone

HEIC photos are decoded in the browser and saved as JPEG, since many upload forms and Windows PCs still can't open HEIC. If you only want the format change without extra compression, use HEIC to JPG.

GIF, BMP and TIFF

These keep their own format, which limits what can be saved. BMP has no compression to tune, and a GIF comes out as a single still frame, so animation is lost. To make these files genuinely small, convert them first with BMP to JPG or TIFF to JPG.

Free, private and without limits on use

You can compress image files free here, with no account, no daily quota and no watermark. Privacy comes from how the tool is built: the compression code loads into your browser and runs there. Your photo is read from your disk, processed in memory and handed back as a download. ImgTask never receives a copy, so there's nothing to delete afterwards.

Each image can be up to 250 MB, with 20 images per batch. Extremely large pictures, above about 100 megapixels, may fail on phones with little memory. If that happens, try a desktop browser or resize the image first.