Documentation

How to Use Real Image Resizer

Quick Start

Overview

Real Image Resizer is a high-performance online tool for resizing images in every major format — JPEG, PNG, GIF, WebP, and HEIC. It supports physical and digital units so you can prepare assets for web, print, or mobile in a single workflow.

1. Upload or Link an Image

Choose your image source from the dropdown on the home page or any format-specific resizer page. Real Image Resizer supports six image input methods:

  • Internal Storage — Select files from your computer or laptop hard drive.
  • Mobile Gallery — Browse photos directly from your smartphone or tablet library.
  • Google Drive — Pick images stored in your Google cloud account.
  • OneDrive — Import files directly from Microsoft’s cloud storage.
  • Dropbox — Access and resize files from your Dropbox account.
  • Image URL — Paste a direct web link to an online image to resize it.

2. Select Unit & Dimensions

Choose the measurement unit that matches your target output. Real Image Resizer supports:

  • Pixels (px) — For digital screens, websites, and app assets.
  • Percent (%) — Scale the image proportionally relative to its original size.
  • Inches (in) — For physical print using configurable DPI resolution.
  • Centimeters (cm) — Metric print dimensions for international standards.
  • Millimeters (mm) — Fine-grain print measurements for precision media.

Use the aspect-ratio lock to maintain proportional scaling automatically. You can also change the output format if you need a different file type from the original.

3. Download & Auto-Cleanup

Once the image is processed, click the download button to save the resized file to your device. Behind the scenes, the original upload is immediately purged from storage — no residual data remains on our servers after your download completes.

The entire pipeline runs on server-side Sharp processing with R2 object storage, ensuring fast throughput and zero persistent storage of your images.

Supported Formats

JPEG / JPG

JPEG is the standard format for photographs and complex digital images. It uses lossy compression to produce small file sizes while maintaining excellent visual quality. Use the JPEG Resizer for website images, social media graphics, and photo archives.

PNG

PNG is the go-to format for graphics, logos, and images that require transparency. It uses lossless compression, meaning no data is discarded during encoding. Use the PNG Resizer when you need crisp edges, alpha channels, or exact pixel reproduction.

WebP

WebP is Google’s next-generation image format offering superior compression — up to 30% smaller file sizes than JPEG at equivalent quality. It supports both lossy and lossless compression as well as transparency. Use the WebP Resizer to optimize your site’s Web Vitals and loading speed.

GIF

GIF is widely used for short animations and simple graphics. It supports both static and multi-frame animated content. The GIF Resizer preserves frame timing, loop settings, and color palettes when scaling animated files.

HEIC

HEIC is Apple’s modern image format used by iPhones and iPads. It offers significantly better compression than JPEG while maintaining higher image quality. The HEIC Resizer can import Apple HEIC photos directly and export them as JPEG, PNG, or WebP for cross-platform compatibility.

Units of Measurement

Pixels (px)

Pixels are the fundamental addressable elements of a digital display. Each pixel represents one point of light on a screen. Use pixels when preparing assets for websites, mobile apps, UI designs, or any screen-based medium. Enter the exact width and height in pixels to resize.

Percent (%)

Percentage scaling resizes the image relative to its current dimensions. 100% keeps the original size; 50% halves both width and height; 200% doubles them. This is the simplest way to quickly scale an image up or down without calculating exact pixel values.

Inches (in)

Inches are a physical print measurement unit. When you enter dimensions in inches, the engine converts them to pixels using your target DPI (dots per inch). Standard presets include 72 DPI (web screens), 150 DPI (draft printing), and 300 DPI (high-quality professional print). Formula: Pixels = Inches × DPI.

Centimeters (cm)

Centimeters are the standard metric unit for physical print dimensions widely used internationally. Like inches, centimeter values are converted to pixels using the selected DPI resolution. 1 inch = 2.54 centimeters. Use cm for European and international print specifications.

Millimeters (mm)

Millimeters provide the finest level of precision for physical print outputs. Use millimeters when preparing assets for business cards, badges, ID cards, labels, or any print medium requiring exact small-scale measurements. 1 cm = 10 mm.

Image Sources

Internal Storage & Mobile Gallery

These two options let you select images directly from your device. Internal Storageaccesses your computer or laptop’s file system — choose from any folder or drive. Mobile Galleryopens your smartphone or tablet’s built-in photo library, optimised for touch-based selection.

Most browsers support drag-and-drop as well. You can drag image files directly onto the resizer widget for instant upload.

Google Drive, OneDrive & Dropbox

These cloud-integrated sources use OAuth-based file pickers to let you select images from your connected accounts without downloading them locally first. The image is streamed directly to our processing engine, resized, and made available for download — no intermediate storage on your device.

  • Google Drive— Picker integrates with Google’s Picker API. Select any image file from your Drive.
  • OneDrive— Microsoft Graph API integration for accessing your OneDrive personal or work files.
  • Dropbox— Dropbox Chooser SDK integration for browsing your Dropbox files.

Image URL

Paste a direct URL pointing to an image hosted on the web. The tool fetches the image from the provided URL, processes it, and returns the resized version. This is useful for resizing remote images without downloading them first.

The URL must point directly to an image file (supported formats: JPEG, PNG, GIF, WebP, HEIC). Some CDN-hosted images with hotlink protection may not be accessible.

Privacy & Security

R2 Auto-Purge

All uploaded images are stored temporarily in an R2 object store — a managed, S3-compatible storage system on Cloudflare's global edge network. The file lifecycle is:

  1. Upload — Your image is transferred to the R2 bucket for processing.
  2. Resize— The Sharp image-processing library reads the file, applies your selected dimensions and format, and writes the output.
  3. Download — The resized file is delivered to your browser for download.
  4. Purge— Immediately after the download completes, both the original and resized files are permanently deleted from R2 storage.

If you close the browser before downloading, the file is purged via a server-side TTL (time-to-live) policy within minutes. No residual image data persists on our servers.

Data Handling Policy

Real Image Resizer is designed as a zero-retention service for processed images. Here is how we handle your data:

  • No logging of image content. Server logs record request metadata (timestamps, file sizes, format conversions) but never store or inspect pixel data.
  • No third-party sharing. Your images are never transmitted to external APIs, analytics services, or third-party processors beyond the Sharp engine running on our own servers.
  • No training data. Uploaded images are never used for machine learning training, dataset collection, or any purpose beyond the immediate resize operation.
  • Encryption in transit. All data transfers use TLS 1.3 encryption between your browser and our servers.
  • Authentication security. User account credentials are hashed and salted using industry-standard bcrypt. OAuth tokens for cloud drive integrations are never stored in plaintext.

For full details, see our Privacy Policy and Terms of Service.

FAQ & Troubleshooting

General Questions

Is Real Image Resizer free?

Yes. Real Image Resizer is completely free with no watermarks, no hidden limits, and no subscription requirements. All resizing features and unit conversions are available to everyone.

What is the maximum file size I can upload?

There is no hard file size limit enforced on the frontend. Very large files (100 MB+) may take longer to process depending on server load. For extremely large batches, consider resizing files individually.

What image sources are supported?

You can upload from Internal Storage (computer hard drive), Mobile Gallery (phone/tablet photo library), Google Drive, OneDrive, Dropbox, or via a direct Image URL. Each source is available from the source selector dropdown on the resizer widget.

Can I resize animated GIFs?

Yes. The GIF Resizer handles both static and multi-frame animated GIFs. Animation speed, loop count, and frame ordering are preserved during resizing.

What happens if I close the tab before downloading?

If you close the tab or browser before downloading the resized image, the file remains in temporary storage for a short period before being automatically purged by our server-side cleanup policy. You will need to re-upload and resize the image again.

Technical Issues

Why is my HEIC file not uploading?

HEIC is Apple’s proprietary format and some browsers may not support HEIC file selection natively. If you experience issues, try using the “Image URL” source or convert the HEIC to JPEG on your device before uploading.

The image URL I pasted is not loading

Ensure the URL points directly to an image file (ending in .jpg, .png, .gif, .webp, or .heic). Some image hosting sites use hotlink protection or require authentication — these URLs will not work. Try downloading the image first and uploading from your internal storage.

My cloud drive picker is not showing files

Cloud drive integrations (Google Drive, OneDrive, Dropbox) require you to grant permission via their respective OAuth consent screens. If the picker opens but shows no files, make sure you are logged into the correct account and have granted file access permissions. Try revoking and re-granting access if the issue persists.

What browsers are supported?

Real Image Resizer supports the latest versions of Chrome, Firefox, Safari, and Edge. Internet Explorer is not supported. For the best experience, use a Chromium-based browser.