Long-Image Compress

Purpose

Specialized compressor for very tall images (chat screenshots, web page full-page captures, scrolling-article screenshots) — splits the image into manageable segments to avoid the browser Canvas size limit that crashes generic compressors. Handles 4K to 50K+ pixel heights, shrinking file size 60-90% while keeping text crisp and readable.

Steps

1. Upload a long image (4,000-50,000+ pixel height typical)
2. Tool detects the height and auto-splits into ~5,000px segments
3. Pick target quality (60-90; 80+ keeps text legible)
4. Choose output: JPEG for mixed content / PNG or WebP for text-only screenshots
5. Start — segments compress with a progress indicator
6. Download a single merged long image

FAQ

Why do generic compressors crash on long screenshots?

Browser Canvas has a max dimension limit (Chrome ~16384px, Safari ~4096px). Generic compressors try to load the full image into one Canvas and hit the wall. We segment-process around this.

How long can the image be?

Tested up to 60,000 pixels tall. Browser RAM is the real limit — a 32GB machine handles 80,000+ pixels.

Will text stay readable after compression?

Quality 80+ keeps text crisp. For very small fonts (<14px) bump to 90, or use PNG / WebP for lossless text rendering.

Chat screenshots — JPEG or PNG?

JPEG quality 85 for mixed text + photos. PNG / WebP for pure text bubbles — they compress text losslessly and often beat JPEG for screenshots.

Can I batch-process multiple long images?

Shorter long-images (under 8,000px) can batch. For very tall ones, process individually to avoid RAM spikes.

Use cases

• WhatsApp / WeChat chat history screenshots for sharing
• Full-page web captures from browser extensions
• WeChat / Substack long articles saved for offline
• Xiaohongshu / Twitter thread captures
• Tall data visualization charts (Sankey, scroll-tellings)

Use cases

Chat history captures, full-page web shots, long articles, thread screenshots — segment processing avoids the Canvas size crash. Text stays crisp.