Compress Image Online

Compress any image online for free — reduce file size for websites, email attachments, and social media without visible quality loss, processed entirely in your browser.

When You Need to Compress Images

Website performance: Uncompressed images from cameras (3–12 MB) create slow-loading pages — compress to under 200 KB for web display.
Email attachments: Gmail limits attachments to 25 MB, Outlook to 20 MB — compress a batch of event photos before emailing clients or colleagues.
Social media uploads: Instagram, LinkedIn, and Twitter re-compress uploaded images — pre-compressing gives you control over quality artifacts.
File sharing: WhatsApp and Slack apply automatic compression that reduces quality — compress manually first for better results.
Cloud storage: Google Photos and iCloud storage fill up fast with raw camera files — compressing archives frees storage without deleting memories.

Compress and Save Size

Step-by-Step Image Compression

Upload your image: Drag and drop a JPEG, PNG, or WebP file — or click to browse. Supports files up to 50 MB.
Choose compression level: Start at 80% quality for general use; reduce to 70% for thumbnails; use 90% for images where quality is critical.
Preview the result: Toggle between original and compressed versions to inspect quality — zoom in to check text, edges, and gradient areas for artifacts.
Adjust if needed: If you see blocking or color banding, increase quality by 5–10% — if the file is still too large, reduce quality by 5%.
Download compressed image: Save the output file — the filename shows the compression ratio achieved (e.g., "photo_compressed_73pct.jpg").

Real-World Use Case

A wedding photographer delivers galleries to clients via a web portal. Raw JPEG files from a Sony A7R V average 15 MB each, and a 400-image gallery totals 6 GB — slow to upload and even slower for clients to browse. After compressing to 85% quality at 2400×1600px (full-screen viewing size), each image averages 800 KB and the gallery drops to 320 MB total — a 95% reduction. The portal loads 5× faster, clients report a smoother browsing experience, and storage costs drop from $40/month to $3/month. High-res downloads still link to original files for print orders. The compression workflow takes 20 minutes vs hours of manual editing.

Best Practices

Always compress originals, not copies: Compressing an already-compressed JPEG adds generational artifacts — always start from the highest-quality source.
Size before quality: Reduce image dimensions to actual display size first, then apply quality compression — unnecessary pixels waste compression budget.
Use WebP when possible: WebP delivers 25–35% smaller files than JPEG at equal quality — convert and compress simultaneously for best results.
Set max dimension for web: Most web layouts display images under 1920px wide — compressing a 6000px image to 1920px removes 90% of pixels before quality settings even matter.
Preserve a copy of originals: Keep original camera files archived — compressed copies are optimized for delivery, not for future re-editing.

Performance & Limits

Supported formats: JPEG, PNG, WebP, GIF, AVIF, BMP input; JPEG, PNG, WebP output.
Maximum file size: Up to 50 MB per image for in-browser processing.
Compression speed: A 10 MB JPEG processes in 1–3 seconds on modern hardware; older mobile devices may take 5–10 seconds.
Lossless mode: PNG images can be compressed losslessly (10–40% size reduction) without any quality loss using color palette optimization.
Batch processing: Process multiple images simultaneously — browser memory limits batch size to approximately 10–20 images at once.

Common Mistakes to Avoid

Compressing screenshots as JPEG: Screenshots with text and sharp UI elements should stay as PNG — JPEG compression creates visible artifacts around text.
Over-compressing for print: Web compression settings are wrong for print — print images need 300 DPI at full size; web display only needs 72–96 DPI.
Not checking mobile rendering: Images look different on small screens — check compressed images on mobile to ensure text in images remains legible.
Forgetting to update alt text dimensions: When resizing + compressing for web, update HTML width/height attributes to prevent layout shifts (CLS).
Compressing animations: Animated GIFs compress poorly with standard image compression — use video formats (MP4, WebM) for animations instead.

Privacy & Security

100% client-side: Your images are processed entirely within your browser using WebAssembly — no image data is uploaded to any server.
No data retention: Images are immediately discarded from browser memory when you navigate away — nothing is stored between sessions.
Safe for sensitive images: Medical, legal, or confidential images can be compressed without any risk of data exposure to third parties.
EXIF metadata control: You choose whether to strip or preserve EXIF data (camera info, GPS coordinates, timestamps) during compression.

Frequently Asked Questions

How do I compress an image for email without losing quality?

For email attachments, target final file sizes under 1 MB per image (under 3 MB total for attachments). For photos: compress JPEG to 75–80% quality and resize to 1200–1800px on the longest side — this yields approximately 200–400 KB per photo with no visible quality loss at email viewing sizes. For images that will be printed by recipients, use 85–90% quality to preserve enough detail. Avoid compressing PNG screenshots below 90% quality as text becomes blurry. When sending multiple images, compress to a ZIP archive after compressing each image — ZIP provides additional 5–15% size reduction on top of image compression.

Why does my compressed image look worse than the original?

Visible quality loss occurs for these reasons: quality set too low (increase to 80–85%); compressing an already-compressed JPEG (artifacts compound — always use original source); image content not suitable for JPEG (screenshots, graphics, and text-heavy images always look worse as JPEG than PNG); compressing at too small a resolution (fine details become muddled); or using GIF for photos (GIF supports only 256 colors — photos look terrible). Solution: for photos, use JPEG or WebP at 80–85%; for screenshots and graphics, use PNG compression (lossless) or WebP with lossless mode; always use the original, highest-quality source file for compression input.

What image size is best for social media?

Optimal dimensions by platform: Instagram square post: 1080×1080px; Instagram landscape: 1080×566px; Instagram story/reel: 1080×1920px; Facebook feed image: 1200×630px; Twitter/X card: 1200×675px; LinkedIn post: 1200×627px; Pinterest: 1000×1500px (2:3 ratio). For all platforms, compress to 80–85% JPEG quality — social platforms re-compress uploaded images anyway, so pre-compressing at high quality gives better final results than uploading a raw camera file that gets aggressively compressed. Keep file size under 8 MB for reliable uploads across all major platforms.

Is there a difference between online image compression and desktop software?

Modern browser-based compressors using WebAssembly (like this tool) achieve quality nearly identical to desktop software like Adobe Photoshop, GIMP, or ImageOptim. The main differences: desktop software offers more granular control over compression algorithms, chroma subsampling settings, and progressive encoding options; batch processing of thousands of files is faster in native apps; desktop tools integrate into editing workflows. For most users compressing up to 50 images at a time, browser-based tools are completely sufficient and have the advantage of requiring no installation, working across any operating system, and keeping images on-device for privacy.