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— make images lighter
  • No sign-up
  • Free
  • Runs in your browser
or paste (Ctrl+V / ⌘V) — fastest for screenshots

JPEG · PNG · WebP · GIF (first frame) · HEIC in Safari only / your originals are never modified

You can pick a purpose first
Enforced by CSP Images never leave this page. You can verify in the developer tools that the page can't send anything. How to check →
How to use / FAQ ↓ More tools ↗

Karuku — Make images lighter (resize, compress, remove location data)

Drop in photos or screenshots and they get lighter on the spot. Pick a purpose (note header, X, OGP, email attachment, upload form, and more) and the dimensions, file-size limit, and format follow.

Ctrl+V Paste to add Ctrl+S Save Esc Close

Settings are saved only in this browser (localStorage), and only when you choose "Remember these settings". Found a bug or have a request? Contact oka-project.

How to use Karuku

  1. Add images — Click "Choose files" or drag and drop anywhere on the page. For screenshots, pasting with Ctrl+V (⌘+V on Mac) is fastest. Processing starts the moment they land.
  2. Decide in one sentence — Tap the underlined words in "3 photos → for note header, up to 1 MB, as JPEG." to change the purpose, size limit, and format. Everything is redone on the spot. Open "Fine-tune" to set the long edge or quality yourself.
  3. Check and save — The size gauge on each card shows whether it fit under the limit. Click a photo to compare before and after at 1:1. Use "Save (ZIP)" for everything at once, or "Save one by one".

Your original files are never modified. Exported files get "-karuku" appended to the name (changeable under Fine-tune).

When it comes in handy

  • Make a header image for note or a blog — Crops to the note header (1280×670) or OGP (1200×630) ratio from the center and keeps it under the size limit. (note is a Japanese blogging platform.)
  • Get under an upload form's "2 MB max" — Phone photos run 4 to 12 MB each. Pick "Upload form" and the quality is tuned automatically until it fits.
  • Attach photos to an email — Bring a batch down to 1600 px on the long edge and under 2 MB, and grab them all as one ZIP.
  • Strip location data before posting — Location, capture time, and camera model embedded in photos are removed as part of the export. The receipt tells you how many were removed.
  • Lighten a screenshot to share — Paste it in and choose PNG or JPEG. Text-heavy screens stay smaller as PNG; photo-like screens as JPEG.

FAQ

Are my images sent anywhere?
No. Decoding, resizing, and compressing all happen inside your browser, and this site has no server-side endpoint that could receive an image in the first place. On top of that, the page's Content-Security-Policy restricts outbound connections. You can verify this yourself in the browser's developer tools (how to check). The only network traffic is page-view and click-count analytics (Google Analytics) used to understand how the site is used; images and file names are never part of it.
Is location data really removed?
Yes. Exports are re-rendered from pixels, so EXIF, GPS, IPTC, and XMP metadata cannot survive structurally. The receipt shows how many input photos had location data and how many had capture time or camera model. The one exception is a photo marked "kept as is (wouldn't get smaller)": that is the original file, metadata included.
Can it open HEIC (iPhone photos)?
In Safari (iOS 17 or later, macOS Sonoma or later), yes. Chrome, Firefox, and Windows can't decode HEIC, so you'll see a note instead. Export as JPEG from the Photos app, or set iPhone Settings → Camera → Formats → Most Compatible to shoot JPEG from the start.
I can't choose WebP
Safari can't write WebP from a canvas, so the WebP option is removed there and JPEG is used instead. Chrome, Edge, and Firefox can.
How many images, and how large?
Up to 50 images at a time, 80 MB each, 500 MB total, and 12,000 px on the long edge. Anything beyond that is refused with a reason. "Stop" halts processing at any time; finished images stay.
My PNG came out larger than the original
PNG is lossless, and photo-like images tend to be larger than as JPEG. If exporting at the same size and format would grow the file, Karuku keeps the original as is and says so. Photos suit JPEG; diagrams, logos, and transparent images suit PNG.
What about animated GIF or SVG?
GIF exports only the first frame as a still image (the animation is lost). SVG isn't a raster image and isn't supported.
It says the image didn't fit under the limit
This appears when the file still exceeds the limit after lowering quality to 40 and shrinking the long edge by 15% three times over. Raise the limit or change the purpose. Karuku won't call a near miss a success.
How is quality decided?
By default it starts at quality 90 and, only when a size limit is set, lowers it until the file fits (down to 40). Without a limit, it stays within a range that keeps the result smaller than the original. To fix a number, open "Fine-tune" and set 40 to 95.
Does it work on phones?
Yes. The save buttons stay pinned at the bottom of the screen, and "Choose files" lets you pick or take a photo. On iPhone a ZIP lands in the Files app, so use "Save one by one" if you want them in Photos.
Are my original files changed?
No. Exports are saved as new files with "-karuku" appended to the name.

Not sure if Karuku fits your workflow? Ask the AI you already use. We prepared a question that has it read this page and llms.txt first — including what the tool can't do.

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