PostOnce Icon
PostOnce
Log inGet Started
 Bookmark us!
Follow the creator on TikTok

Free Image Resizer - Resize Photos Online Instantly

Resize images online in seconds with our free tool. Perfect for social media, web, and print. No server upload - all processing happens in your browser for privacy and speed.

🖼️

or drag and drop your image here

Supports JPG, PNG, WEBP • Max size: 10MB

Table of Contents

  1. Image Resizer Tool
  2. Resize for Social Media
  3. Why Use Our Image Resizer
  4. How to Resize Images
  5. Best Practices
  6. Common Image Sizes
  7. Frequently Asked Questions

Resize for Social Media Platforms

Choose a platform for optimized preset dimensions

instagram logo

Instagram

4 presets

facebook logo

Facebook

4 presets

twitter logo

Twitter/X

3 presets

linkedin logo

LinkedIn

4 presets

youtube logo

YouTube

3 presets

tiktok logo

TikTok

2 presets

pinterest logo

Pinterest

3 presets

threads logo

Threads

2 presets

bluesky logo

Bluesky

3 presets

reddit logo

Reddit

3 presets

Why Use Our Image Resizer

Our free online image resizer offers unique advantages that set it apart from other tools. Here's why thousands of users choose PostOnce for resizing images:

  • No Upload Required: All processing happens in your browser. Your images never leave your device, ensuring complete privacy and security.
  • Maintain Aspect Ratio: Smart padding prevents content loss. Add white, black, transparent, or custom colored backgrounds to fit target dimensions without cropping.
  • Multiple Formats: Support for JPG, PNG, and WEBP formats. Convert between formats while resizing to optimize file size and quality.
  • Platform Presets: One-click resize for Instagram, Facebook, Twitter, LinkedIn, YouTube, TikTok, Pinterest, Threads, Bluesky, and Reddit with optimal dimensions.
  • Instant Results: See real-time preview before downloading. Compare original and resized images side-by-side with dimension and file size information.
  • Completely Free: No sign-up, no watermarks, no limits. Resize unlimited images at no cost with full features available to everyone.

How to Resize Images Online

Resizing images with our tool is simple and fast. Follow these four easy steps:

1

Upload Your Image: Click the upload button or drag and drop your photo into the tool. Supports JPG, PNG, and WEBP files up to 10MB.

2

Choose Dimensions: Select a preset size (square, portrait, landscape, or platform-specific) or enter custom width and height. Toggle aspect ratio lock if needed.

3

Preview Results: See before and after comparison with dimensions and file sizes. Adjust fit mode (contain, cover, exact) and background color as needed.

4

Download: Save your resized image instantly. Files are automatically named with dimensions for easy organization.

Best Practices for Image Resizing

Choose the Right Dimensions

Each social media platform has specific size requirements. Instagram prefers square (1080x1080) or portrait (1080x1350), while Twitter works best with landscape (1200x675). Use our platform-specific presets to ensure your images display perfectly.

Maintain Quality

Balance file size and visual quality using the quality slider. For social media, 85-90% quality is ideal - it significantly reduces file size while maintaining visual quality. Always start with high-resolution originals for best results.

Consider Aspect Ratio

Maintain aspect ratio to avoid distortion and stretching. Use "contain" fit mode with padding to reach target dimensions without cropping. This preserves all your image content while fitting platform requirements.

Optimize for Web

Reduce file size for faster loading times. Use JPG format for photographs (smaller files) and PNG for graphics with text or transparency. WEBP offers the best compression but has limited support on older browsers.

Use Appropriate Formats

JPG is ideal for photos with many colors and gradients. PNG works best for graphics, logos, and images with text or transparency. WEBP provides superior compression for modern web applications. Choose based on your content and target platform.

Common Image Sizes for Social Media

Quick reference for optimal image dimensions on major social media platforms:

PlatformSize TypeDimensionsAspect Ratio
InstagramSquare Post1080×10801:1
InstagramPortrait Post1080×13504:5
InstagramStory1080×19209:16
FacebookFeed Post1200×6301.91:1
TwitterTweet Image1200×67516:9
LinkedInFeed Post1200×6271.91:1
YouTubeThumbnail1280×72016:9
PinterestPin1000×15002:3
TikTokVideo Cover1080×19209:16
ThreadsPost1080×10801:1
BlueskyPost1000×10001:1
RedditPost1200×67516:9

For detailed size guides with profile pictures, covers, and more, visit our platform-specific image resizer pages above.

Frequently Asked Questions

What is an image resizer?
An image resizer is a tool that changes the dimensions (width and height) of an image file. Our free online image resizer allows you to resize photos instantly in your browser without uploading to a server. You can resize images for social media, web, print, or custom dimensions.
How do I resize an image online for free?
Upload your image by clicking the upload button or dragging it into the tool. Choose your target dimensions (either a preset or custom size), preview the result, and click download. Our image resizer processes everything in your browser for privacy and speed.
Does resizing an image reduce quality?
Enlarging images can reduce quality, but our tool uses smart algorithms to minimize quality loss. When downsizing, quality is generally maintained. You can adjust the quality slider (1-100) to balance file size and visual quality. For best results, start with a high-resolution original image.
What image formats can I resize?
Our image resizer supports JPG, JPEG, PNG, and WEBP formats. You can also convert between formats when resizing - for example, resize a PNG and download as JPG for smaller file size.
Can I resize images without cropping?
Yes! Our tool offers a "contain" fit mode that adds padding around your image to reach target dimensions without cropping. You can choose the padding color (white, black, transparent, or custom) to match your needs.
What are the best image sizes for social media?
Each platform has different requirements: Instagram posts (1080x1080), Instagram stories (1080x1920), Facebook posts (1200x630), Twitter images (1200x675), LinkedIn posts (1200x627), YouTube thumbnails (1280x720), and Pinterest pins (1000x1500). Use our platform-specific presets for instant resizing.
Is there a file size limit for resizing images?
We recommend images under 10MB for optimal performance. Since processing happens in your browser, very large files may slow down older devices. For best results, use images between 1-5MB.
Can I resize multiple images at once?
Currently, our tool resizes one image at a time. Batch processing is planned for a future update. For now, resizing is so fast (under 3 seconds) that processing multiple images individually is still very efficient.
Do I need to create an account to resize images?
No account needed! Our image resizer is completely free with no sign-up required. Simply upload, resize, and download. Your images are never stored on our servers.
Why should I use your image resizer instead of others?
Unlike other tools, we process images entirely in your browser (no server upload), offer platform-specific presets for all major social networks, allow padding without cropping, support multiple output formats, and provide instant preview. Plus, it's completely free with no watermarks or limits.
What's the difference between maintain aspect ratio and custom dimensions?
Maintaining aspect ratio keeps your image's original proportions - if you resize width, height adjusts automatically to prevent distortion. Custom dimensions let you set exact width and height, which may stretch or compress the image. We recommend maintaining aspect ratio unless you need exact dimensions.
Can I resize images on mobile devices?
Yes! Our image resizer works on all devices - desktop, tablet, and mobile. The interface is responsive and touch-friendly. However, for the best experience with large files, we recommend using a desktop or tablet.

Ready to Automate Your Content Distribution?

Join thousands of creators who save hours every week with PostOnce's crossposting automation.

Start Free TrialView Pricing