Image Resizer — Resize by Pixels, Percentage, Longest Edge, or Print Size

What an image resizer actually does

An image resizer changes the pixel dimensions of a photo or graphic — for example from 4000×3000 down to 1080×1080 for an Instagram post, or up from a small scan to the pixel count needed for a 300 DPI print. People search for it under many names — resize image, photo resizer, image dimension changer, change image size, resize picture, image size converter — but they all mean the same operation: set a new width and height and let the browser recompute every pixel.

Unlike a compressor, which shrinks the file without changing dimensions, a resizer changes the dimensions themselves (and the file size usually changes as a side effect). This tool gives you four ways to specify the target — exact pixels, a percentage of the original, a longest-edge limit, or a physical print size converted to pixels using a DPI value — so you never have to do the arithmetic by hand. It also resizes multiple images in one batch and downloads them as a ZIP, which is what most people actually need when they say "resize my photos for the web."

Every resize operation here runs locally in your browser with the HTML5 Canvas API. The image is never uploaded, stored, or logged. That matters for two reasons: it is private, and it is fast — there is no upload wait and no server queue. Close the tab and the images are gone from memory.

How to resize an image (or a whole batch)

1. Add your images. Drag one or more files onto the upload area, click to browse, or paste from the clipboard (Ctrl+V / Cmd+V). JPEG, PNG, WebP, GIF, and BMP are supported. The first image is shown in the preview; all images share the same resize settings.
2. Pick a resize method. Use Pixels for an exact target size, Percentage to scale uniformly, Longest edge to cap the longer side (ideal for mixed-orientation batches), or Print size to enter centimetres/millimetres/inches plus a DPI setting. With the aspect-ratio lock on, changing one dimension auto-fills the other.
3. Adjust orientation and fit. Rotate 90° or flip horizontally/vertically before resizing. If your target ratio differs from the original, choose Stretch (distort), Contain (fit inside with a background fill), or Cover (fill and crop). A one-click preset fills in any social, display, or print size instantly.
4. Compare and download. Drag the split divider to inspect the original against the resized result. Pick an output format and quality, check the estimated file size, then download a single file or the whole batch as a ZIP. Recent sizes are saved as chips for one-click reuse.

Pixels, percentage, longest edge, and print size — when to use which

Pixel mode is for exact targets: a 1080×1080 Instagram post, a 1200×630 Facebook link preview, a 2000×2000 Amazon product photo, or a form that demands specific dimensions. It is the mode you reach for when a platform or application tells you exactly what size it wants, and it is what most people mean by "resize image to 1080x1080" or "change image dimensions."

Percentage mode is for uniform scaling: shrink a folder of photos to 50%, enlarge a small graphic to 200%, or experiment with how an image looks at 75% of its original. Because percentage applies to both dimensions equally, the aspect ratio never changes and there is no distortion — which makes it the safest mode for a batch resize of mixed images.

Longest-edge mode sets only one number — the size of the longer side — and the tool computes the shorter side automatically while preserving the aspect ratio. It is the fastest way to make a folder of mixed landscape and portrait photos all fit under a maximum size, for example "longest edge 2000 px", without working out width and height for each one separately. Ecommerce sellers and bloggers use it constantly.

Print mode converts physical dimensions to pixels using a DPI (dots per inch) value. Enter 4×6 inches at 300 DPI and you get 1200×1800 pixels; the same physical size at 150 DPI is 600×900 pixels. This is the mode to use when you are preparing a photo for printing, a poster, or a document where the physical size and print quality matter more than the raw pixel count.

💡 Quick rule of thumb: 300 DPI for anything you hold in your hand (photos, brochures, business cards), 150 DPI for large posters viewed from a metre away, 72–96 DPI for anything shown on a screen. More DPI than that just makes a bigger file with no visible improvement.

Image resizer, photo resizer, resize image online — same tool, different names

People search for this tool under many names. They all land on the same operation — changing the pixel dimensions of an image — and this tool handles every one of them:

• Image resizer / resize image online — the general term; all four modes, single or batch.
• Photo resizer / resize photo — usually photographs destined for print or social; the Print and Preset modes cover it.
• Change image size / image dimension changer — exact pixel dimensions; Pixel mode with aspect-ratio lock.
• Reduce image size / shrink image — usually downscaling for the web; Percentage or Longest-edge mode.
• Increase image size / enlarge image / upscale image — percentage above 100%; note the softness limit explained below.
• Resize JPG / resize PNG / resize WebP — format-specific; upload any of them and export to any of them.
• Batch image resizer / resize multiple images — drop a folder of files and download a ZIP.
• Resize image for Instagram / for print / for web — use the matching preset or Print mode.

Stretch, Contain, and Cover explained

These three fit modes decide what happens when your target width-to-height ratio does not match the original image's ratio — for example putting a landscape photo into a square Instagram frame.

• Stretch ignores the original ratio and warps the image to exactly fill the target. Use it only for abstract graphics or patterns where distortion is invisible; for photos it makes faces and objects look squashed.
• Contain scales the whole image to fit inside the target, keeping every pixel visible. The leftover space (letterbox bars) is filled with your chosen background colour. Use it when the entire image must be visible — a product photo on a white background, a logo, a document scan.
• Cover scales the image to completely fill the target and crops whatever overflows. Nothing is distorted and there are no bars, but you lose the edges. Use it for social posts and hero images where a full-bleed look matters more than showing every corner.

Pixels vs DPI vs PPI — the confusion that ruins every resize

Pixels are the actual dots in the image file — 1200×1800 is a fixed amount of data. DPI (dots per inch) and PPI (pixels per inch) describe how densely those pixels are printed or displayed: the same 1200×1800 pixel file prints at 4×6 in at 300 DPI, or 8×12 in at 150 DPI. Changing the DPI metadata alone does not change the pixel count; it only changes how big the image comes out of a printer. In this tool's Print mode, changing the DPI does change the pixel dimensions, because you are asking for a physical size at a given density — and that is the correct way to prepare a file for print.

For screens, DPI is irrelevant. A 1200-pixel-wide image is 1200 pixels wide on any monitor; what changes is how many physical screen dots it occupies. This is why "72 DPI for web" is a harmless convention but not a technical requirement — you can leave it at any value and the image displays identically. What actually matters for the web is the pixel width and the file size.

Resizing for print — sizes, DPI, and the math

Print resizing is just pixel arithmetic: pixels = physical inches × DPI. A 4×6 in photo at 300 DPI is 1200×1800 pixels; the same print at 600 DPI is 2400×3600 pixels (four times the data, rarely needed). The Print mode in this tool does the conversion instantly for inches, centimetres, and millimetres, with DPI from 72 to 1200.

Social media, display, and web preset sizes

Every preset below is available with one click in the tool. These are the current recommended upload sizes — uploading at exactly these dimensions prevents the platform from re-compressing and softening your image.

Resizing for the web and page speed

Most websites display images at 600–1600 px wide. If you upload a 6000-pixel photo into a 700-pixel box, the browser downloads the full multi-megabyte file and then squashes it — wasting bandwidth and making the page load slowly on mobile. Resizing to the display width (or twice that for Retina screens) before uploading is the single most effective web-performance fix most site owners never make. A common rule: 800–1200 px for article images, 1920 px for full-width hero images, 400–800 px for thumbnails and cards.

Retina and other high-DPI displays pack two or more physical pixels into one CSS pixel, so an image displayed at 600 px CSS width should ideally be 1200 px wide to look crisp. Beyond 2× (3× and 4× on flagship phones), the visible improvement for photographs is negligible while the file size keeps growing — so 2× is the practical sweet spot. A batch resize to "longest edge 1600 px" is usually perfect for an entire website's content images.

Resize vs crop vs compress — which do you need?

These three operations are independent and people constantly confuse them. Resizing changes the pixel dimensions of the whole image — every pixel stays, just fewer of them. Cropping deletes a portion of the image and keeps the rest at full resolution; cropping to a square and then resizing is how you make a square Instagram post from a landscape photo (the Cover fit mode in this tool does the crop step for you). Compression reduces file size without changing pixel dimensions — a 1200×900 JPEG becomes a smaller 1200×900 JPEG by discarding high-frequency detail. For pure compression to a target KB, use the companion Image Quality Changer; for reducing dimensions only, this resizer is the right tool.

Resizing and image quality — what is possible and what is not

Downscaling rarely hurts perceived quality — a properly resampled smaller image often looks sharper on screen, because detail below the display's ability to show it is removed. This tool uses high-quality canvas smoothing and, for large reductions, progressive halving (repeatedly halving the dimensions until close to the target) to avoid aliasing and jagged edges. Upscaling is the opposite: making an image larger than its original pixel count softens it, because the browser must invent pixels that were never captured. Past about 150–200%, ordinary resizing produces visibly soft results; for genuine enlargement with detail recovery you need an AI upscaler, which reconstructs plausible detail rather than interpolating between existing pixels.

⚠ Resizing removes EXIF metadata (camera model, GPS, timestamp) because the browser re-encodes the image through canvas. That is usually good for privacy, but if you need the original metadata keep the original file alongside the resized one.

Batch resizing and ZIP download

Drop as many images as you like onto the upload area — there is no fixed count limit beyond your device's available memory. The same resize settings (mode, dimensions, fit mode, rotation, output format, quality) apply to every file, and each file's row shows its computed new dimensions. You can download any single file from its row, download the currently previewed image with the main Download button, or — when more than one image is loaded — download everything together as a single ZIP archive. This is the fastest way to prepare a folder of product photos for a website, a set of images for social media, or scans for email.

Where people use an image resizer

• Ecommerce product photos — resize to the marketplace's exact dimensions (Amazon 2000×2000, eBay 1600×1600, Etsy 2000×2000) in one batch.
• Social media — one-click presets for Instagram, Facebook, YouTube, Twitter/X, LinkedIn, Pinterest, and TikTok.
• Websites and blogs — shrink 4000-pixel camera photos to display width so pages load fast.
• Forms and applications — many portals demand an exact pixel size or a maximum dimension; longest-edge mode handles the cap.
• Print preparation — convert physical sizes (4×6, 5×7, A4) to pixels at 300 DPI.
• Email and messaging — reduce oversized attachments so they actually send.

Common mistakes when resizing images

• Forgetting the aspect-ratio lock and typing width and height independently, which stretches the image. If you need a different shape, use Contain or Cover instead of Stretch.
• Upscaling a tiny image and expecting it to be sharp. It will not be. Start from the highest-resolution source you have; upscaling is a last resort.
• Using 72 DPI for print. 72 DPI is a screen convention. At 72 DPI a 4×6 in print is only 288×432 pixels — visibly blocky. Use 300 DPI for prints you hold close.
• Uploading a 6000-pixel photo to a website. Resize to the display width (or 2× for Retina) first. It makes pages load dramatically faster.
• Re-saving a JPEG repeatedly. Each JPEG save discards a little more detail. If you will edit and re-save several times, work from PNG or the original and export JPEG only once at the end.
• Confusing file size with pixel size. A "200 KB limit" is a compression problem (use the Image Quality Changer); a "1080×1080 requirement" is a resize problem (this tool).

Limitations

• Animated GIFs are resized as a single still frame — animation is not preserved through canvas re-encoding.
• HEIC support depends on your browser and operating system; if an HEIC file fails to load, convert it to JPEG first.
• Upscaling beyond the original resolution softens the image; this tool does not perform AI super-resolution.
• This tool sets dimensions, not a strict byte target. For an exact KB/MB limit, use the Image Quality Changer.
• For downscaling with a choice of six resampling methods (including area averaging and progressive halving controls), use the dedicated Image Downscaler.
• Very large batches (hundreds of multi-megapixel images) may be slow on low-memory devices; process them in smaller groups.

Privacy and data handling

This resizer runs entirely in your browser. Your images are read from disk or clipboard, processed with the Canvas API, and written back to a download — they are never transmitted to any server, and nothing is logged or stored. There is no account, no watermark, and no usage limit. Recent-size chips are stored only in your own browser's localStorage and can be cleared at any time with the Clear button.

Frequently asked questions

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