Arbenger Image Compressor is a free, browser-based tool that shrinks your PNG, JPEG, and WebP images without uploading them to any server. Every pixel stays on your machine. This guide walks you through every feature — from compressing a single photo to batch-processing dozens of images at once.
100% Private
Your images never leave your browser. All compression happens locally using Web Workers and the Canvas API. No uploads, no servers, no tracking.
What You'll Learn
1. Uploading Images
There are three ways to get images into the compressor:
Drop images here
Drag & Drop
Drop files directly onto the upload zone
...paste, or
PNG, JPG, WebP
Click to Browse
Click the zone to open your file picker
Paste from clipboard
Clipboard Paste
Press Ctrl+V to paste from clipboard
Supported Formats
Upload one image for single mode with before/after comparison, or multiple images for batch mode with ZIP export.
2. Compressing an Image
After uploading, you'll see the preview on the left and the controls panel on the right. Here's the compression workflow:
Set Quality
Use the quality slider (1–100) to control the compression level. Lower values produce smaller files with more visible artifacts. For PNG, quality controls color reduction.
Choose Output Format
Keep the original format or convert to JPEG, PNG, or WebP. WebP typically achieves the smallest file sizes.
Click Compress
The image is compressed in a Web Worker off the main thread, so the UI stays smooth. You'll see the result with file size comparison instantly.
Download
Hit the download button to save your compressed image. The filename is editable — change it before downloading if needed.
COMPRESS CONTROLS
QUALITY CONTROL
QUALITY
80
OUTPUT FORMAT
FILENAME
3. Before & After Comparison
After compressing, the before/after slider lets you compare the original and compressed images side by side. Drag the handle to reveal more of either side.
Scroll to zoom — zoom up to 2000% to inspect compression artifacts at the pixel level.
Drag to pan — when zoomed in, click and drag to move around the image. Both sides move together.
Pinch to zoom — on mobile, use two-finger pinch to zoom in and out.
4. Format Conversion
Choose your output format based on your needs. The compressor can keep the original format or convert to any supported type:
| Format | Compression | Quality Slider | Best For |
|---|---|---|---|
| JPEG | Lossy | Controls quality (0-100) | Photos, complex imagery |
| WebP | Lossy | Controls quality (0-100) | Web use, smallest files |
| PNG | Color quantization | Controls color count (100 = lossless) | Graphics, screenshots, logos |
If the compressed result is larger than the original (same format), the compressor keeps the original automatically — your file will never get bigger.
5. Target Size Mode
Instead of setting a quality level, you can specify a maximum file size. The compressor uses binary search to find the highest quality that fits within your target.
TARGET SIZE MODE
MAXIMUM FILE SIZE
Original: 1.3 MB
Validation — the target cannot exceed the original file size. The input highlights amber and the compress button is disabled if it does.
Can't reach target? — if the smallest possible file still exceeds your target, the compressor shows a warning with the achievable minimum.
6. Batch Processing
Upload more than one image and the tool automatically switches to batch mode. All images share the same compression settings and are exported as a single ZIP file.
BATCH MODE WORKFLOW
Upload 2+
Drop multiple images
Configure
Shared quality & format
Auto-Name
Naming patterns
Download ZIP
All images in one file
Upload 2+ images
Drop or browse multiple files
Configure settings
Shared quality, format
Auto-name files
Sequential, prefix, or template
Download ZIP
All images in one file
Drag to reorder — rearrange images by dragging them in the list.
Duplicate detection — re-uploading the same file is automatically skipped with a toast notification.
Auto-naming patterns — choose from sequential (img-1, img-2), prefix-original, original-suffix, number-only, or custom templates with {name} and {n} tokens.
ZIP export — all compressed images are packaged into a single ZIP file.
7. Pro Tips
Use WebP for the smallest file sizes
WebP typically produces files 25-34% smaller than JPEG at equivalent quality, with transparency support. Convert your PNGs and JPEGs to WebP for the best web performance.
PNG quality 100 still compresses
Quality 100 for PNG means lossless re-encoding — zero visual change. But UPNG's optimized encoder often produces smaller files than the original by using better compression filters. You might see 10-30% reduction with no quality loss.
Target size for email attachments
Need to send photos under a size limit? Switch to Target Size mode, set your limit (e.g., 500 KB), and the compressor finds the highest quality that fits. No guesswork needed.
Zoom in to check quality
Use the scroll wheel (or pinch on mobile) to zoom up to 2000% on the before/after slider. This lets you inspect compression artifacts at the pixel level before downloading.
Keyboard shortcuts
Press Ctrl+V to paste images from clipboard, and Esc to clear all images.
Ready to compress?
Try the Image Compressor now — no signup, no upload, no cost.
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