How to Resize Images for Instagram, X, LinkedIn and YouTube in Chrome or Firefox

Short answer: each social platform crops or squeezes images that don't match the shape it expects. To get a clean result, resize the photo to the platform's dimensions before you upload it, and choose crop (with the subject in frame) or fit (with a border) instead of stretching. In Chrome or Firefox you can do this with Image Resizer, which has 22 presets, 18 of them for Instagram, Facebook, X, LinkedIn, YouTube and WhatsApp, and resizes the image inside your browser.

Why the same photo looks wrong on different platforms

A phone photo is usually 4:3 or 3:4. An Instagram square post is 1:1, a YouTube thumbnail is 16:9, a LinkedIn banner is roughly 4:1, and a story is 9:16. When the shape doesn't match, the platform decides for you: it crops the edges, adds bars, or scales the image down so far that text becomes unreadable.

Resizing first puts that decision back in your hands. It also keeps file sizes sensible. Uploading a 12-megapixel photo for a 400 × 400 profile picture means the platform re-compresses it, and its compression is rarely as kind as yours.

The sizes Image Resizer uses

These are the dimensions built into Image Resizer 1.0.0. They are common starting points, not official limits, and platforms change their guidance over time. YouTube is a good example: its thumbnail help page now recommends 3840 × 2160 for video thumbnails, with a minimum width of 640 pixels and a 16:9 shape. The 1280 × 720 preset is the same shape, and the 4K preset matches YouTube's current recommendation. LinkedIn is another: its Page image specifications now list 1512 × 256 pixels as both the minimum and the recommended size for a Page cover image, larger than the 1128 × 191 Company Cover preset, so type 1512 × 256 as a custom size for a company Page. Check the platform's own help page if an upload is important.

Platform	Preset	Size (px)	Shape
Instagram	Post (Square)	1080 × 1080	1:1
Instagram	Post (Portrait)	1080 × 1350	4:5
Instagram	Post (Landscape)	1080 × 566	about 1.91:1
Instagram	Story / Reel	1080 × 1920	9:16
Instagram	Profile Photo	320 × 320	1:1
Facebook	Post	1200 × 630	about 1.91:1
Facebook	Cover Photo	820 × 312	about 2.6:1
Facebook	Story	1080 × 1920	9:16
X	Post Image	1200 × 675	16:9
X	Header Photo	1500 × 500	3:1
X	Profile Photo	400 × 400	1:1
LinkedIn	Post	1200 × 627	about 1.91:1
LinkedIn	Personal Banner	1584 × 396	4:1
LinkedIn	Company Cover	1128 × 191	about 5.9:1
YouTube	Thumbnail	1280 × 720	16:9
YouTube	Channel Art	2560 × 1440	16:9
WhatsApp	Profile Photo	500 × 500	1:1
WhatsApp	Status	1080 × 1920	9:16

The other four presets are general sizes: Full HD (1920 × 1080), 4K UHD (3840 × 2160), App Icon (512 × 512) and Favicon (32 × 32). If none of them fit, you can type your own width and height, up to 16000 × 16000 pixels.

Crop, fit or stretch: pick the right mode

The size is only half the job. When the photo's shape differs from the target, something has to give, and Image Resizer lets you pick what.

• Crop fills the whole frame and cuts off whatever doesn't fit. This is the right choice for most posts, stories and thumbnails. Set the focal point on the subject (a face, a product, a line of text) so the cut happens around it instead of through it.
• Fit keeps the whole photo and fills the leftover space with a border. You choose the border colour, or transparent if you export as PNG or WebP. Use it when nothing may be cut off, such as a screenshot, a chart or a poster.
• Stretch forces the photo into the new shape. People and logos look squashed or pulled, so it is rarely what you want. It is fine when the source already has the right shape and you only need a different pixel size.

Banners deserve extra care. A LinkedIn banner or an X header is very wide and short, and the profile photo sits on top of part of it. Keep important text away from the edges and the lower left, and preview the result on the platform before you rely on it.

Step by step in Chrome or Firefox

The steps are the same in both browsers. On Firefox it needs version 142 or later.

1. Install Image Resizer from the Chrome Web Store or Firefox Add-ons.
2. Open it from the browser toolbar and drop in a photo, paste one from the clipboard, or right-click an image on a web page and choose Resize this image.
3. Pick a preset, for example Instagram Post (Portrait), or enter your own size.
4. Choose Crop and pick the focal point nearest the subject on the 3 × 3 grid (for example top or bottom-left), or choose Fit and a border colour.
5. Pick the output format. JPG is the safe default for photos; PNG suits screenshots and graphics with text; WebP is smaller but not accepted everywhere.
6. Optionally, for JPG or WebP, set a target file size, and the quality is adjusted to reach it.
7. Download the file.

If you post the same kind of image every week, save the settings as a profile. The Free plan keeps up to 3 saved profiles.

One photo for several platforms

A launch, an event or a new blog post often needs the same image in four or five shapes. On the Free plan you can add up to 5 images per run and download them one by one or as a single ZIP, so the simplest approach is one run per platform size.

Pro, a one-time €7.99 purchase, adds export packs: select several presets at once and get every size from one run. It also removes the 5-image limit per run. A Pro key works on multiple browsers, so you can use the same purchase in Chrome and Firefox.

Keep file sizes reasonable

Bigger is not always better for social uploads. Most platforms re-compress what you send, and some forms have strict limits. A few rules of thumb:

• Don't upload far above the preset size. A 1080-pixel-wide Instagram post gains nothing from a 6000-pixel original.
• Use JPG for photos and keep quality high; the difference between high and maximum quality is usually invisible but the file is much larger.
• Use PNG for screenshots, text and logos, where JPG artefacts show around sharp edges.
• If a site rejects the file as too large, set a target size. How to Resize an Image to a Specific Size in KB explains how dimensions and quality work together.

Photos straight from an iPhone are often HEIC files, which Chrome and Firefox can't open. Image Resizer reads HEIC and HEIF directly, so you can convert to JPG and resize in the same step.

What happens to your photos

Resizing, cropping and conversion happen inside the browser on your computer; the photo isn't uploaded to a conversion service and there is no account to create. When you use the right-click option, the extension downloads the image from the site it's on, just as the browser does when it shows it. The extension does use the network for some features, such as checking a Pro license with UnifyBrowse's license server. The 1.0.0 release notes describe which features connect and what they send.

FAQ

What size should an Instagram post be?

At the time of writing, Instagram's help page says photos up to 1080 pixels wide keep their resolution when the shape is between 1.91:1 (landscape) and 3:4 (portrait), so 1080 × 566 up to 1080 × 1440. Image Resizer's Instagram presets use that 1080-pixel width: 1080 × 1080 for square, 1080 × 1350 for portrait (4:5) and 1080 × 566 for landscape.

What size is a YouTube thumbnail?

YouTube's help page recommends 3840 × 2160 with a 16:9 shape and a minimum width of 640 pixels. The 1280 × 720 preset has the same shape and a smaller file; use the 4K preset if you want to match the recommendation exactly.

Why does my LinkedIn or X banner look cut off?

Banners are very wide, and the platform overlays your profile photo, and the visible area can change with screen size. Use the banner preset, keep text near the centre, and check the result on both a phone and a computer.

Can I resize images for social media without uploading them to a website?

Yes. Image Resizer resizes and converts images inside Chrome or Firefox, so the photo isn't sent to an online resizer.

Is Image Resizer free?

Yes. The Free plan includes all 22 presets, custom sizes, crop, fit and stretch, target file sizes, HEIC import, up to 5 images per run and 3 saved profiles. Pro is a one-time €7.99 purchase for export packs and larger runs.

Image Resizer is free on Chrome and Firefox. More about the extension: Image Resizer.