Resize Images Before Uploading Or Sharing Them
Resize PNG, JPG, WebP, and AVIF files by pixels, percentage, or physical units for upload forms, website assets, social media posts, cover images, product listings, and cleaner sharing.
The tool keeps the original image format where possible and returns a resized copy.
How to use Image Resizer
Upload one supported image file.
Choose exact dimensions, percentage resizing, or a social media preset based on the result you need.
Download the resized image in the original format where possible.
Resize images by pixels, percentage, cm, mm, or inches
Use the In size tab when you know the exact width or height you need. The page supports pixels for screen-first work, plus centimeters, millimeters, and inches for print or document workflows where physical dimensions matter more than raw pixels.
Use the As percentage tab when you want to shrink or enlarge the image relative to the original file without calculating the output size manually. The page also shows the original size and expected output size in pixels, so you can verify the result before you resize.
Social media image size presets
Use the Social Media tab to resize images for Facebook feed posts and cover photos, Instagram square posts, portrait posts, stories and reel covers, X posts and headers, YouTube thumbnails, LinkedIn posts and profile banners, Pinterest pins, and TikTok covers. Preset mode uses a centered crop so the exported image matches the target aspect ratio exactly.
Facebook image sizes
Facebook Feed Post 1200 x 630; Facebook Cover Photo 851 x 315
Instagram image sizes
Instagram Square Post 1080 x 1080; Instagram Portrait Post 1080 x 1350; Instagram Story / Reel Cover 1080 x 1920
X image sizes
X Post 1600 x 900; X Header 1500 x 500
YouTube image sizes
YouTube Thumbnail 1280 x 720
LinkedIn image sizes
LinkedIn Post 1200 x 627; LinkedIn Profile Banner 1584 x 396
Pinterest image sizes
Pinterest Pin 1000 x 1500
TikTok image sizes
TikTok Video Cover 1080 x 1920
Why this helps in real workflows
A website upload form rejects images that are too large visually.
A marketplace listing needs a smaller image size.
A profile or cover image has to fit a more specific slot.
A teammate needs the same image in cleaner dimensions before reuse.
Common problems and fixes
The image is too wide for the upload area.
Resize the width down first and keep the aspect ratio on so the image stays natural.
The form expects a specific image box.
Set both width and height, and turn aspect ratio off only if the destination requires exact dimensions.
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Frequently asked questions
How do I resize an image online?
Upload one supported image, choose the width and optional height, then download the resized copy.
Can I resize an image in centimeters, millimeters, or inches instead of pixels?
Yes. Switch the size unit from pixels to cm, mm, or inches, then enter the resolution in PPI so the tool can convert the physical size to the right pixel dimensions.
Can I resize an image by percentage?
Yes. Use the percentage tab to scale the original image from 1% up to 200%. This is useful when you want to shrink or enlarge an image without calculating exact output dimensions yourself.
Which social media image sizes are supported?
The social media tab includes presets for Facebook feed posts and cover photos, Instagram square posts, portrait posts, stories and reel covers, X posts and headers, YouTube thumbnails, LinkedIn posts and profile banners, Pinterest pins, and TikTok covers.
What size should an Instagram post or Story be?
A common Instagram square post size is 1080 by 1080 pixels, a portrait post is 1080 by 1350 pixels, and an Instagram Story or reel cover is 1080 by 1920 pixels. Those presets are built into the tool.
What size should a YouTube thumbnail be?
A standard YouTube thumbnail size is 1280 by 720 pixels. You can choose the YouTube thumbnail preset to resize the image to that exact size.
What happens if my image does not match the social media aspect ratio?
Social media preset mode uses a centered crop so the final image matches the selected platform dimensions exactly. If you want to avoid cropping, use the size or percentage tabs instead.
Will this change the file format too?
No. This tool keeps the original image format where possible and focuses on changing the dimensions.
When should I keep the aspect ratio?
Keep it when you want to avoid stretching the image. Turn it off only when a specific fixed box is required.