Resize images by pixel dimensions or percentage with aspect ratio lock. Supports PNG, JPG, and WebP output. Shows before/after file size estimate, original dimensions, and output preview. Batch resize up to 5 images at once.
Click or drag to upload up to 5 images at once. Supported formats: PNG, JPG, JPEG, WebP, GIF, BMP. Original dimensions and file size are shown for each uploaded image.
Enter new width or height in pixels — with aspect ratio lock enabled, the other dimension updates automatically. Or switch to percentage mode and enter a scale factor (e.g. 50% to halve both dimensions). Choose output format (PNG, JPG, WebP) and quality (for JPG/WebP).
Click Resize & Download to process all images. Each is drawn to a canvas at the new size and downloaded. For batch processing, files are downloaded sequentially. File sizes before and after are compared.
Upscaling (making larger) always reduces quality because the browser must interpolate new pixels — the result looks blurry or pixelated. Downscaling (making smaller) generally preserves quality well. For the best downscaling quality, enable imageSmoothingQuality="high" on the canvas (which this tool does). For upscaling with AI enhancement, tools like Topaz Gigapixel or Let's Enhance provide better results.
PNG: lossless, no quality loss, supports transparency, larger file sizes — best for logos, graphics, screenshots. JPG: lossy compression, smaller files, no transparency — best for photographs. WebP: modern format with better compression than both PNG and JPG, supports transparency and animation — best for web use when broad browser support is available (all modern browsers support WebP).
Aspect ratio lock maintains the original width-to-height proportions as you resize. If you change the width, the height adjusts automatically to keep the image from being stretched or squished. Disabling it lets you enter any width and height independently, which distorts the image.
Email clients typically display images at screen resolution (72-96 DPI). For a wide email column (600px width), resize to exactly 600px wide. For retina screens, 1200px wide at 2× scale is common. Keep file sizes under 500KB for email attachments. Use JPG at 80% quality for photos, PNG for graphics with transparency.
Yes — select PNG as the output format. The canvas preserves the alpha channel during resizing. If you select JPG, transparency is lost (converted to white background). WebP also supports transparency when selected as the output format.
The browser Canvas API handles images up to the browser's texture size limit, typically 16,384×16,384px. For most practical purposes (photos up to 50MP), the tool works fine. Very large images (over 50MP) may cause memory warnings or browser crashes on low-memory devices.
