Every platform size as JPEG
Some sizes have a lower limit, down to 100 KB.
Nothing is uploaded. Your images stay on this device.Nothing is uploaded
How it worksDrop images or a folder anywhere on this page
Or paste one. They stay on this device.
Up to 50 images, 60 MB each. JPEG, PNG, WebP, AVIF or GIF.
Every platform size as JPEG
Some sizes have a lower limit, down to 100 KB.
4 widths as WebP and AVIF, with a code snippet
5 display banners and an email header
Instagram Story
1440 × 2560
Instagram portrait
1440 × 1800
Square post
1200 × 1200
Pinterest pin
1000 × 1500
LinkedIn post
1200 × 628
X post
1600 × 900
YouTube thumbnail
1920 × 1080
Facebook cover
851 × 315
If you change a crop afterwards, only the files that changed are made again.
Social makes every platform size as JPEG. Website makes four widths as WebP and AVIF, and adds a <picture> code snippet for each image to the ZIP. Ads and email makes five display ad sizes and an email header.
You can also make your own pack with any sizes, and send it to a colleague or client as a link. They open the link and have the same pack, with no account needed. The pack travels in the part of the link after the #, which browsers do not send to any server.
| Output | Size in pixels | Notes |
|---|---|---|
| Instagram Story | 1440 × 2560 | Keep the subject out of the top 14% and bottom 35%, which can be covered |
| Instagram portrait | 1440 × 1800 | 4:5 |
| Square post | 1200 × 1200 | 1:1 |
| Pinterest pin | 1000 × 1500 | 2:3 |
| LinkedIn post | 1200 × 628 | 1.91:1 |
| X post | 1600 × 900 | 16:9 |
| YouTube thumbnail | 1920 × 1080 | 16:9, and held under 2 MB so it can also be uploaded from a phone |
| Facebook cover | 851 × 315 | Held under 100 KB, as Facebook suggests for the best loading speed |
| Display ads | 300 × 250, 336 × 280, 300 × 600, 728 × 90, 320 × 100 | Held under the 150 KB limit for Google image ads |
| Email header | 1200 × 400 | Twice the usual 600-pixel email column, for sharp screens |
| Website | 1600, 1200, 800 and 400 wide | Keeps the shape of your image, and skips any width larger than your image |
Platforms change these. The sizes here were last checked in November 2026.
The resizer looks for the best quality that stays under your target. It never changes the pixel size to get there, because a platform size has to stay exact.
Some images are too detailed to reach a small target. When even the lowest quality is too big, the file is still made, marked as over target on screen, and listed in the report in the ZIP, so you can raise the target or simplify the image.
Images are sorted into a folder per pack, then a folder per image, and named with their output and size, such as Social/launch/launch-square-1200x1200.jpg.
report.txt lists any files that failed, missed their target, became larger than the original, were enlarged from a smaller source, or have a subject the platform may cover. The Website pack adds snippets.html, with the code for each image.
Metadata such as camera details and location is left out of every file, because the images are drawn fresh from their pixels.
Something else? contact@getoxtro.com
No. Your images are processed on your own device, by code running in your browser, and never reach our server. If you accept analytics in the cookie banner, we count runs and downloads, but never file names or images.
Yes. There is no account, no watermark, and you can use the files commercially.
The source image is smaller than that output, so it had to be enlarged. The crop is marked with how much. A larger source fixes it.
The Website pack skips widths larger than your image, because enlarging would add file size without adding detail.
Not yet. You can drop a folder and every image inside it is added, but the ZIP is organised by pack and image name. Images with the same name get separate folders, so nothing is overwritten.
Made by Oxtro
Oxtro connects your WhatsApp number by QR code, so your team can share one inbox, run campaigns to people who opted in, and send messages from your own code.