Does this tool upload my images anywhere?

No. All resizing happens entirely in your browser using the HTML5 Canvas API. Your images are read locally, processed in memory, and downloaded directly to your device. Nothing is sent to any server.

What is the difference between resize modes?

Exact Pixels sets the output to precisely the dimensions you enter. Percentage scales the image by a factor (50% = half size). Fit Within scales the image down so it fits inside a bounding box while keeping the original aspect ratio — useful for thumbnails or max-width constraints. Presets are common sizes for social media and web use.

What output format should I choose?

JPEG is best for photos and produces the smallest files. PNG is lossless and best for screenshots, logos, or images with transparency. WebP is the modern choice — smaller than JPEG at equal quality and supports transparency like PNG. Keep 'Auto' to preserve the original format.

Image Tool

Image Resizer

Resize JPEG, PNG, and WebP images by pixels, percentage, or social media preset — entirely in your browser, no upload required.

How to Resize an Image

Four resize modes for every use case — done in seconds.

Drop or Select an Image

Drag your image onto the drop zone or click to open the file picker. Supports JPEG, PNG, WebP, GIF, and BMP.

Choose a Resize Mode

Pixels — set exact width and height. % Scale — scale proportionally. Fit Within — scale to fit a bounding box. Presets — pick a social media or web size.

Set Dimensions

Enter your target dimensions. Lock the aspect ratio to prevent distortion. In percentage mode, drag the slider or type a value.

Choose Format & Quality

Keep the original format or convert to JPEG, PNG, or WebP. Adjust quality for JPEG and WebP to balance file size and sharpness.

Click Resize Image

The tool renders your image at the new dimensions using the Canvas API and shows a before/after comparison slider.

Download

Click "Download Resized Image" to save the result. The file is named with "-resized" appended so it won't overwrite your original.

How It Works — The Logic

All processing runs in your browser using native Web APIs.

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Canvas API Resize

Images are drawn onto an HTML5 Canvas element at the target dimensions using drawImage(). The canvas is then encoded to a Blob via toBlob().

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Aspect Ratio Lock

When locked, changing width auto-calculates height as: newH = newW × (origH ÷ origW), and vice versa. Keeps the image from stretching.

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Fit Within Algorithm

Scale = min(maxW ÷ origW, maxH ÷ origH). If scale > 1 the image is not enlarged. Output = origW × scale × origH × scale. Always keeps aspect ratio.

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Social Media Presets

30+ presets for Instagram, Twitter/X, Facebook, LinkedIn, YouTube, and web use — all with the correct dimensions for each platform's guidelines.

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Bilinear Interpolation

Browsers use high-quality bilinear or bicubic interpolation when drawing scaled images on Canvas — significantly sharper than nearest-neighbour.

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100% Private

Your image never leaves your device. FileReader loads it into memory, Canvas processes it, and the result is offered as a download. No network calls.

Frequently Asked Questions

Common questions about image resizing.

Scaling down (making an image smaller) generally preserves quality well — you're just reducing the number of pixels. Scaling up (making an image larger) will reduce sharpness because the browser must interpolate new pixels that didn't exist. There is no information to recover from a small image. For enlarging, use AI upscaling tools that can infer detail. This tool is best for scaling down and for exact social media dimensions.

Exact Pixels sets the output to precisely the dimensions you enter, even if that means stretching or squishing the image (unless aspect ratio is locked, in which case it crops to fit). Fit Within scales the image proportionally so it fits inside a bounding box without cropping or distorting. A 3000×2000 image fitted within 1200×1200 will become 1200×800 (keeping the 3:2 ratio). Use Fit Within for thumbnails and max-width constraints; use Exact Pixels when you need a precise canvas size for social media.

PNG uses lossless compression, which means every pixel is stored exactly. JPEG uses lossy compression that discards subtle color information the eye barely notices. A 1920×1080 PNG of a photograph might be 2–5MB, while the same image as JPEG at quality 80 might be 200–400KB. PNG is best for images with text, sharp edges, transparency, or screenshots. JPEG is best for photographs. WebP gives you the smallest file size for both types at equivalent quality.

Platform requirements change, but common 2025 guidelines: Instagram square post 1080×1080, Instagram portrait 1080×1350, Instagram Story 1080×1920, Twitter/X post 1600×900, Twitter/X header 1500×500, Facebook cover 1640×624, LinkedIn banner 1584×396, YouTube thumbnail 1280×720, OG/share image 1200×630. Always check each platform's current guidelines, as they update periodically.

After resizing, both the original and the resized image are rendered in a stacked container. The original image has a clip-path applied that reveals only the left portion up to the handle position. The resized image is visible in the right portion. Dragging the handle updates the clip-path percentage in real time, giving you a smooth reveal of the changes. The range input below provides keyboard and fine-control access to the same value.

Not fully. The Canvas API only captures the first frame of an animated GIF. If you resize a GIF, the output will be a static image of frame 1, not an animated GIF. For animated GIF resizing, you need a server-side tool or a dedicated GIF processor. This tool will load the GIF's first frame and allow you to resize and save it as a JPEG, PNG, or WebP.

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