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GridSlice

Resize, crop, split a 3×3 grid, or slice a panorama carousel.

No login, no upload — your image is decoded and sliced right here in the browser.

100% on your deviceNothing uploadedFree
Target size

Start with an image

On-device · nothing uploaded

Drop an image, or tap to choose

HEIC · JPG · PNG · WebP · GIF · AVIF — up to 6000px

Best-effort & for single photos only. If it fails, download the image and drop it in — that always works.

Everything here runs on your device — no upload, no account. HEIC photos your browser can't read itself are decoded by libheif, a separate LGPL-3.0 component fetched only when you open one. libheif licence & notice

GridSlice — questions, answered

How do I resize a photo for Instagram without losing quality?

Open GridSlice, drop in your image, and pick an Instagram preset — square (1:1), portrait (4:5) or story (9:16) — and it resizes and crops to the exact pixel size in your browser. Everything happens on your device, so nothing is uploaded and your original file isn't compressed by a server.

How do I split one photo into a 3x3 grid for my Instagram feed?

Upload your photo to GridSlice and choose the 3x3 grid option — it slices the image into 9 perfectly aligned tiles you post in reverse order to build one big picture across your profile. The cuts are done locally in your browser and download as ready-to-post squares.

What are the correct Instagram image sizes for posts and stories?

Instagram feed posts are 1080x1080 (square), 1080x1350 (portrait 4:5) or 1080x566 (landscape), and Stories and Reels covers are 1080x1920 (9:16). GridSlice has one-tap presets for square, portrait and story so you don't have to remember the numbers.

How do I make a swipeable panorama carousel for Instagram?

Load your wide panorama into GridSlice and use the carousel slicer — it cuts the image into evenly sized slides that line up when viewers swipe through your post. Pick 2 to 10 slides, and each slice is exported on-device, no upload needed.

Is there a free Instagram photo resizer that works offline?

Yes — GridSlice is completely free and runs entirely in your browser, so after the page loads it works offline with no account, login or app install. Your images never leave your device, which makes it safe for private or unpublished photos.

How do I crop a picture to fit Instagram without it getting cut off?

In GridSlice, choose the target ratio (square, portrait or story) and drag to position the crop so the important part of your photo stays in frame before you export. Because it crops to Instagram's exact dimensions, the image fills the post cleanly instead of being auto-cropped by the app.

Can I use iPhone HEIC photos, or do I need to convert them first?

Yes — drop a .HEIC file straight in and GridSlice converts it on your device. Safari decodes HEIC natively; Chrome, Firefox and Edge download a one-time 1.5 MB HEIC decoder the first time you open one, and the export keeps the photo the right way up.

How do I make an image smaller than 1 MB for Instagram?

Pick JPEG or WebP in GridSlice, set Fit under to 1 MB, 500 KB, 200 KB or your own number, and it re-encodes on your device until the file lands under that size — then tells you the quality it used. PNG is lossless with no quality setting, so it cannot target a size, and Instagram re-encodes whatever you upload anyway.

About GridSlice

GridSlice is a free, on-device image toolkit for Instagram that resizes and crops your photos to the exact sizes Instagram expects — square (1080x1080), portrait (1080x1350) and story (1080x1920) — in a single tap. Beyond resizing, it splits one photo into a clean 3x3 grid so you can build a big feature image across your profile grid, and slices a wide panorama into evenly matched slides for a swipeable carousel post.

Everything runs 100% in your browser. Your images are never uploaded to a server, so the tool works offline and is safe for private, client or unpublished photos — no login, no account, no watermark and no app to install. iPhone HEIC files are read on-device too, and a portrait photo keeps the rotation its EXIF tag asks for instead of landing sideways. Just drop in a file, pick a preset, position the crop, and download post-ready images in seconds.

GridSlice is part of shotMod, a free hub of privacy-first Instagram tools by SourceStrong AI. Once your grid, carousel or perfectly sized post is live and pulling comments and DMs, its sibling tool DMrun (dmrun.com) can turn that engagement into customers automatically.