Redimensionner des images en ligne
Changez les dimensions de vos images à n'importe quelle taille. Gratuit, privé et instantané — tout se fait dans votre navigateur.
100% Privé — Vos fichiers ne quittent jamais votre appareil. Tout le traitement se fait dans votre navigateur.
Déposez votre image ici
ou cliquez pour sélectionner — JPG, PNG, WebP supportés
Taille d'origine
Préréglages rapides
Résultat
Comment fonctionne le redimensionneur d'images ?
Cet outil utilise l'API Canvas intégrée à votre navigateur pour redessiner votre image aux nouvelles dimensions que vous spécifiez. L'ensemble du processus s'exécute localement sur votre appareil — vos images ne sont jamais envoyées vers un serveur.
Tips for Better Image Resizing
- Lock the aspect ratio — Keep the aspect ratio locked (the default) to prevent your image from looking stretched or squished. This ensures width and height scale proportionally whenever you change either dimension.
- Use percentage presets for quick scaling — The 25%, 50%, and 75% presets are the fastest way to create thumbnails or reduce file size. A 50% reduction cuts the pixel count by 75%, dramatically shrinking the file while keeping proportions perfect.
- Pick dimension presets for specific targets — Use built-in presets like 1920×1080 (Full HD), 1280×720 (HD), or 800×600 for common web and social media sizes.
- Downscale rather than upscale — Shrinking an image preserves quality because the browser discards pixels. Enlarging forces the browser to interpolate new pixel data, which causes blurriness.
- Choose the right output format — After resizing, export as WebP for the smallest file size, JPEG for photographs, or PNG when you need transparency.
- Resize before compressing — If you plan to both resize and compress, resize first. Reducing dimensions first means the compressor has fewer pixels to process.
- Check the final dimensions display — Always verify the output dimensions shown below the width and height inputs before downloading.
When to Resize Your Images
- Social media profile pictures and banners — Each platform has specific dimension requirements (e.g., 1080×1080 for Instagram posts, 1500×500 for Twitter/X headers). Resizing ensures your images display perfectly without awkward cropping by the platform.
- Website and blog optimization — A 4000×3000 camera photo is far too large for a blog post. Resizing to 1200px wide before uploading cuts load time dramatically.
- Email-friendly images — Attaching full-resolution photos to emails wastes bandwidth and may exceed size limits. Resizing to 1280×960 or smaller makes images load instantly in email clients.
- Thumbnail generation — Use the 25% preset to quickly create thumbnail versions of product photos, gallery images, or portfolio pieces.
- Print preparation — When preparing images for print, resize to match your print size at 300 DPI — for example, a 4×6 inch print needs a 1200×1800 pixel image.
- E-commerce product listings — Marketplaces like Amazon, Etsy, and eBay have minimum and maximum image size requirements.
Questions fréquentes
Le redimensionnement réduit-il la qualité ?
Agrandir une image au-delà de sa taille d'origine peut causer un léger flou, car le navigateur doit interpoler de nouveaux pixels. Réduire les dimensions préserve bien la qualité. Pour de meilleurs résultats, réduisez ou restez proche de la taille d'origine.
Qu'est-ce que le verrouillage du ratio ?
Lorsque le ratio est verrouillé (par défaut), modifier la largeur ajuste automatiquement la hauteur pour conserver les mêmes proportions — et vice versa. Cela empêche votre image d'être étirée ou écrasée. Vous pouvez le déverrouiller si vous avez besoin de proportions personnalisées.
Que sont les préréglages rapides ?
Les préréglages vous permettent de redimensionner rapidement vers des dimensions courantes. Les préréglages en pourcentage (25%, 50%, 75%) sont relatifs à la taille d'origine. Les préréglages de dimensions (1920×1080, 1280×720, etc.) définissent des valeurs exactes en pixels — utile pour les réseaux sociaux, les miniatures ou la publication web.
What are the best image sizes for social media?
Common social media sizes include 1080×1080 for Instagram posts, 1200×630 for Facebook shared images, 1500×500 for Twitter/X headers, and 1280×720 for YouTube thumbnails. Use the dimension presets in ImgLab to quickly hit these targets, or type custom dimensions with aspect ratio lock enabled.
Can I make a small image larger without losing quality?
Upscaling a raster image always involves some quality loss because the browser must generate new pixels that did not exist in the original. Small increases (up to 150%) are usually acceptable, but doubling or tripling an image's size will produce noticeable blurriness. For the best upscale results, start with the highest-resolution source image you have.
Can I resize multiple images at once?
The resize tool currently processes one image at a time, allowing you to fine-tune dimensions for each photo. For batch resizing, you can quickly process images one after another — just drop a new image after downloading the previous one. Each image retains your last-used dimensions and settings for faster workflow.
Does resizing change the DPI/PPI of my image?
ImgLab resizes by pixel dimensions, not by DPI. DPI (dots per inch) only matters for print — it defines how many pixels fit in a physical inch. A 3000×2000 image printed at 300 DPI produces a 10×6.67 inch print. The tool changes the pixel count; your print software controls DPI when you output to paper.