Discord vs Slack vs LINE 2026: Image Upload Limits Compared
Too Lazy to Read the Docs? One Table Is All You Need
Every time you try to share an image on Discord, Slack, or LINE, you get hit with "file too large." Each platform has its own limits, and the official docs are scattered all over the place.
This post consolidates every limit into a single table — look it up, copy it, use it.
Image Upload Limits Across All Three Platforms
The data below reflects real-world testing as of February 2026, covering both free and top-tier paid plans:
| Comparison | Discord | Slack | LINE |
|---|---|---|---|
| Free plan file limit | 25 MB | 1 GB (since April 2024) | No explicit cap on originals, but compressed sends have limits |
| Paid plan file limit | Nitro: 500 MB / Nitro Basic: 50 MB | Same as free | No paid-tier difference |
| Supported image formats | JPEG, PNG, GIF, WebP, APNG | JPEG, PNG, GIF, WebP, SVG | JPEG, PNG, GIF |
| Upload compression | None (original preserved) | None (original preserved) | Compresses to ~2048 px longest edge by default |
| Max preview size | Embed preview max 4096×4096 px | Inline preview ~360×480 px | Chat bubble preview ~1024 px |
| Animated GIF support | Full support, auto-play | Full support | Supported but large files won't auto-play |
| Image retention | Permanent (CDN links expire and refresh) | Free plan retains 90 days of message history | Permanently stored in chat history |
| Original file download | Original downloadable | Original downloadable | Must select "Original Quality" to keep the original |
| EXIF handling | EXIF preserved | EXIF preserved | Stripped on compressed sends; preserved on original-quality sends |
| API upload support | Bot API / Webhook | Web API / Webhook | Messaging API (requires Official Account) |
Compression Behavior in Detail
Discord: No Compression, but Embed Preview Limits Apply
Discord does not compress uploaded images. If you upload a 10 MB PNG, the recipient downloads the same 10 MB PNG.
There's a catch, though: embed previews have their own size limits. If the image is too large, Discord generates a smaller thumbnail for the chat view. Users need to click "Open in Browser" to see the full resolution.
In late 2024, Discord updated its CDN policy — image links now include expiring signature parameters. Sharing a copied image link outside Discord may result in a dead link after some time.
Slack: Generous File Limits, but Free-Tier Message History Is Capped
Since April 2024, Slack raised the free-plan file upload limit to 1 GB — matching the paid plan. Very generous.
The catch: the free plan only retains 90 days of message history. Images older than 90 days aren't deleted, but the messages are hidden — you'll need to upgrade to access them.
Slack doesn't compress uploaded images but auto-generates multiple thumbnail sizes (80 px, 360 px, 480 px, etc.), serving different resolutions on different devices.
LINE: Most Aggressive Compression by Default, but Has an Original-Quality Option
LINE compresses the most aggressively of the three. Under default send mode:
- Images with a longest edge exceeding 2048 px get downscaled
- JPEG quality drops to roughly 70–75%
- PNGs are converted to JPEG (except those with transparency)
- EXIF data is stripped
LINE does provide an "Original Quality" send option. Tap the "Original Quality" button next to the image picker in a chat to send uncompressed originals. Many users either don't know about this feature or skip it for convenience.
Real-world test: A 4032×3024 px, 5.8 MB iPhone photo sent via LINE's default mode becomes 2048×1536 px at ~680 KB. That's roughly 88% compression.
Hidden Limits You'll Run Into
Beyond the official specs, there are practical gotchas:
- Discord Webhook images: Images sent via Webhook have an embed preview cap of 6000×6000 px — exceeding it hides the preview
- Slack external link previews: Slack's unfurl preview for external image links caps at 5 MB — larger images won't expand
- LINE bulk sends: Selecting more than 50 images at once may cause some to fail silently — no error message
- Discord GIF limits: Non-Nitro users uploading GIFs over 8 MB will see them displayed as static images
Practical Workarounds
When you hit these limits, here are ways around them:
Option 1: Compress Before Sending
Use tools like TinyPNG or Squoosh to compress first — you can typically cut file size by 50–70% with negligible quality loss.
Option 2: Share via Cloud Storage Links
Upload to Google Drive or Dropbox and share the link. No compression, but recipients need an extra click to view and the preview isn't as seamless.
Option 3: Use an Image Hosting Service
Upload to an image hosting service and paste the direct link into your chat. Most messaging apps will auto-expand the preview.
lpic.cc is an image host that works well with messaging apps. Upload and get a share link — it previews correctly on Discord, Slack, and LINE. Uploaded images are not compressed, have no resolution limits, and EXIF privacy data is automatically stripped.
Note that files on lpic.cc have a retention period (varies by plan), so it's not suitable for permanent archival. If you need long-term storage, save a separate copy to your personal cloud drive.
Option 4: Discord Nitro / Slack Paid Plan
The brute-force solution — pay to upgrade. Discord Nitro raises the limit to 500 MB; Slack's paid plan unlocks full message history.
Best Approach by Scenario
| Scenario | Recommended Approach |
|---|---|
| Sharing high-quality photography | LINE Original Quality mode / image hosting link |
| Sharing screenshots in a Discord channel | Direct upload (25 MB is plenty) |
| Sending design files in a Slack workspace | Direct upload (1 GB cap is more than enough) |
| Preserving original quality for multiple recipients | Image hosting link or cloud storage |
| Sharing GIF memes | Discord (best GIF support) |
| Avoiding compression without installing extra tools | Upload to image host, then share the link |
FAQ
Q1: Is Discord's free 25 MB limit enough?
For typical image sharing, absolutely. A 4K JPEG photo is usually 5–15 MB, and PNG screenshots are typically 1–5 MB. Unless you're sending ultra-long screenshots, high-res RAW files, or large GIFs, 25 MB rarely becomes a bottleneck.
Q2: Is LINE's post-compression quality noticeably worse?
On a phone screen, the difference is minimal. On a desktop monitor or when cropping into details, it becomes obvious. For text screenshots, document photos, or anything where fine detail matters, strongly recommend using "Original Quality."
Q3: Does Slack's free plan delete images after 90 days?
No — they're not deleted, but the messages are hidden. You can't view or search messages and images older than 90 days in the UI. Upgrading to a paid plan restores access. If you're worried about losing important files, download backups or save copies to cloud storage.
Q4: Which platform is most GIF-friendly?
Discord, by far. It supports APNG and WebP animations, auto-plays smoothly, and Nitro users can use custom GIF emoji. Slack and LINE support GIFs too, but their preview sizes and auto-play behavior aren't as polished.
Q5: Is there any way to completely avoid compression on LINE?
Two ways: first, use the "Original Quality" button; second, send the image as a file (long-press the image → select "Send as File"). This skips compression and format conversion. The downside is that the recipient gets a file rather than an image preview and has to download it manually.