How this resizer works, and why nothing is uploaded

Everything happens in this tab. When you add a file the browser reads it into memory, draws it onto a canvas at the size you picked, and hands the result straight back as a download. No copy of the image reaches SideBoo or anyone else, so there is no upload to wait through and no file left on a server that somebody has to remember to delete.

Each output is centre-cropped rather than squashed. Ask a 4:3 photo for a 1:1 square and the tool scales the image to cover the square, then trims the overflow evenly from both sides — faces and subjects near the middle survive. That is what you want for a profile picture, and the wrong call when the important part of the frame sits at an edge.

The limits are worth knowing up front: 10 images per run, 8 output sizes each, and 6000 × 6000 pixels as the largest custom size. Input has to be JPG, PNG or WebP — HEIC from an iPhone and TIFF from a scanner both need converting first. There is no “keep it under 500 KB” field either; lower the quality slider and pick JPG or WebP when you need a smaller file.

The sizes people ask for most

Every size below is already a preset — tick it and export, no typing needed.

1080 × 1080 — the square post, under “Other sizes”.
1080 × 1920 — stories on Instagram, Facebook and Snapchat, and TikTok video.
1920 × 1080 — the 16:9 preset, for landscape video and slide covers.
1200 × 630 — the link preview card Facebook, LinkedIn and X render.
1200 × 1200 — the Facebook square post.
851 × 315 — the Facebook cover photo.
1128 × 191 — the LinkedIn profile banner; 400 × 400 for the profile photo.
512 × 512 and 1024 × 1024 — app and store icons, under “Icons & squares”.

This tool is made by SideBoo, a Chrome extension that turns ⌘K into one search box for your tabs, history and bookmarks. See what it does.

Frequently asked questions

Are my images uploaded or saved?

No. Images are read and processed only in this browser tab; they are never sent to SideBoo servers.

How are images resized?

The tool scales and centre-crops each image to fill the selected dimensions without empty space.

How many images can I resize?

You can add up to 10 images at a time and export up to 8 sizes for each image.

How do I resize an image to 1920x1080?

Open the “Other sizes” group and pick the 16:9 preset, which is exactly 1920 × 1080. For any other exact dimensions, use the custom size fields and type the width and height in pixels.

How do I resize a photo for a Facebook cover photo?

Open the Facebook group and select “Cover photo”, which is 851 × 315 pixels. The same group also has the 1200 × 630 link preview, the 1200 × 1200 square post, the 1080 × 1920 story and the 1920 × 1005 event cover.

What size should a LinkedIn banner or profile photo be?

The LinkedIn group covers all four: a 1128 × 191 profile banner, a 400 × 400 profile photo, a 1200 × 627 landscape post and a 627 × 1200 portrait post.

How do I make a picture square?

Pick any square preset — 1080 × 1080 under “Other sizes”, 1200 × 1200 for Facebook, or 320 × 320 for an Instagram profile photo. The image is centre-cropped, so nothing is stretched.

Which image formats are supported?

You can add JPG, PNG and WebP files, and export to any of those three. BMP, TIFF and HEIC files are not supported as input — convert them first.

Can I resize an image to a specific file size, like under 2MB?

Not to an exact target. There is no “compress to 512 KB” field. What you can do is lower the export quality slider and choose JPG or WebP instead of PNG — both cut the file size substantially — then check the result and adjust.

How do I resize an image to 512x512, 1024x1024 or 3000x3000?

Open “Icons & squares” and tick the size you need — 3000 × 3000, 1024 × 1024, 600 × 600, 512 × 512, 240 × 240, 128 × 128 and 100 × 100 are all there as presets. Any other dimensions go in the custom size fields, up to 6000 × 6000. Images are centre-cropped, so a square target keeps the middle of the frame.