PTT, Dcard, Bahamut Image Embed Rules 2026: Complete Forum Posting Guide
If you've ever posted an image link in a forum and wondered why some forums show an inline preview while others display a raw URL — you're not alone.
The answer is simple: every forum handles image links differently. PTT, Dcard, and Bahamut — Taiwan's three biggest forums — each have their own rules. Once you understand how each one works, your images will display correctly every time.
This guide walks you through each forum's image posting method step by step, even if you've never done it before.
Quick Reference Table
For those in a hurry, here's the summary:
| Forum | Preview Method | Supported Formats | Recommended Size | Direct Link Required? | Recommended Host |
|---|---|---|---|---|---|
| PTT (BBS) | Plain text link | N/A | N/A | N/A | Any host |
| PTT (Web/App) | Auto-expand image | JPG, PNG, GIF | < 10 MB | Yes | Imgur, ImgBB, lpic.cc |
| Dcard | og:image preview card | JPG, PNG, GIF, WebP | < 20 MB | No (but recommended) | Imgur, ImgBB |
| Bahamut | Manual image tag | JPG, PNG, GIF | < 5 MB | Yes | Bahamut built-in, Imgur |
Now let's break down each forum in detail.
PTT Image Posting Rules
PTT is arguably Taiwan's oldest and most iconic forum. Its unique characteristic: at its core, PTT is a BBS (Bulletin Board System) — a purely text-based system. Think of it as a text-only chat room where images must be shared via external links.
BBS Terminal Mode
If you access PTT through traditional BBS clients like PCMan or Welly, you can only paste links. Your image URL appears as plain text, and other users must manually copy the link and open it in a browser to view the image.
The steps are straightforward:
- Upload your image to any image host
- Copy the direct link (the URL ending in .jpg, .png, etc.)
- Paste the URL directly into your post
- Leave a blank line before and after the URL for better readability
PTT Web Version and Apps
The good news: when others view your post through PTT's web version (e.g., term.ptt.cc) or third-party apps (Mo PTT, JPTT, etc.), most image links are automatically expanded into inline previews.
But here's the key point: not all image host links will expand correctly.
PTT web clients and apps rely on URL pattern detection to decide whether to expand a link. The rules are:
- The URL must be a direct link (pointing directly to the image file)
- The URL must end with an image extension (.jpg, .png, .gif)
- Some apps additionally support Imgur short links (e.g.,
https://i.imgur.com/xxx)
Think of "direct link" this way: when you open the URL in a browser, you see the image immediately — not a webpage that contains the image.
Recommended PTT Posting Workflow
- Upload your image to a host that supports direct links (Imgur, ImgBB, lpic.cc all work)
- Copy the "Direct Link" — not the "Share Page Link"
- Verify the link ends in .jpg, .png, or .gif
- Paste into your post with blank lines above and below
For example, a correct direct link looks like this:
https://i.imgur.com/abcdefg.jpg
Not like this (this is a share page link and won't be expanded):
https://imgur.com/abcdefg
Dcard Image Posting Rules
Dcard's user experience is much more modern than PTT. It features a WYSIWYG editor (think of it like a Word-style editing interface), and its image handling is smarter.
Direct Upload
The simplest method is using Dcard's built-in upload:
- In the post editor, click the image icon in the toolbar
- Select the image you want to upload
- The image automatically uploads to Dcard's servers and inserts into your post
This is the easiest approach, but the downside is that images are tied to Dcard. If you want to share the same image elsewhere, you'll need a separate image host.
Pasting Image Links
If you've already uploaded an image to another host, you can paste the link directly. Dcard will attempt to parse the link and generate a preview. It uses two parsing methods:
Direct image links: If you paste a URL ending in .jpg, .png, .gif, or .webp, Dcard displays the image directly in the post.
og:image preview: If you paste a webpage link (e.g., an image host's share page), Dcard reads the page's og:image tag (essentially the page's designated preview image) and displays it as a preview card.
This means even non-direct links can show image previews on Dcard, as long as the host's share page has og:image properly configured. However, direct links still produce the best results — the image embeds at original size rather than appearing as a small preview card.
Recommended Dcard Posting Workflow
- For Dcard-only posts, the built-in upload is most convenient
- For cross-platform sharing, upload to an image host first, then paste the direct link
- Dcard supports WebP — if your host provides WebP direct links, you get smaller files and faster loads
Bahamut Image Posting Rules
Bahamut has the strictest image posting rules of the three forums, but it's not complicated once you understand them.
Bahamut Built-in Image Host
Bahamut has its own image upload space, and it's the most reliable way to post images there:
- Click "Insert Image" in the post editor
- Select "Upload from computer"
- The image uploads to Bahamut's servers (truth.bahamut.com.tw)
Using Bahamut's built-in host guarantees maximum compatibility — images will always display correctly. The downside is limited storage capacity for free accounts.
Using External Image Hosts
If you want to use external hosts, be aware of Bahamut's whitelist system. Bahamut doesn't accept all image hosts — it maintains an approved source list. Based on my testing, these hosts' direct links display correctly on Bahamut:
- Imgur (
i.imgur.com) - Bahamut built-in (
truth.bahamut.com.tw) - Google-related image services
Links from other hosts may be blocked or fail to render.
Image Tag Syntax
In Bahamut posts, you have two ways to insert images:
Editor mode: Use the image button in the toolbar — the editor automatically generates the correct syntax.
Manual input: In plain text editing mode, use Bahamut's BBCode syntax:
[img]https://i.imgur.com/abcdefg.jpg[/img]
Note the difference from PTT — PTT only requires pasting the link, while Bahamut requires wrapping it in [img] tags.
Recommended Bahamut Posting Workflow
- Prioritize Bahamut's built-in image upload
- For external hosts, choose Imgur (best compatibility)
- Keep images under 5 MB (larger files may fail to upload)
- Use the editor's image button to avoid syntax errors
Format Support Differences Across Forums
Beyond posting methods, the three forums also differ in format support:
| Format | PTT Web | Dcard | Bahamut |
|---|---|---|---|
| JPEG (.jpg) | ✅ | ✅ | ✅ |
| PNG (.png) | ✅ | ✅ | ✅ |
| GIF (animated) | ✅ | ✅ | ✅ |
| WebP | Some apps | ✅ | ❌ |
| AVIF | ❌ | ❌ | ❌ |
| SVG | ❌ | ❌ | ❌ |
Bottom line: JPEG and PNG are the safest choices — all three forums support them. Animated GIFs also work everywhere. WebP offers smaller file sizes but currently only Dcard fully supports it; using WebP on PTT or Bahamut may cause issues.
Common Reasons Images Fail to Display
If your image isn't showing up in a forum post, it's usually one of these reasons:
Link isn't a direct link: You pasted the host's share page URL instead of the image's direct link. Fix: look for the "Direct Link" or "Direct URL" option in the host's interface.
Image too large: Some forums or hosts limit image resolution or file size. Compress to under 5 MB before uploading.
Host is blocked: Especially on Bahamut — if your host isn't whitelisted, the image simply won't render. Switching to a supported host usually fixes it.
HTTPS issue: Most forums now require HTTPS image links (not HTTP). If your image link starts with http://, try changing it to https://.
Image Host Recommendations by Forum
Based on these test results, here are the best host choices for each forum:
PTT only: Imgur or ImgBB work well — direct link format compatibility is solid, and most PTT apps expand them correctly.
Dcard only: The built-in upload is most convenient. For external hosts, both Imgur and ImgBB direct links display well on Dcard.
Bahamut only: Prioritize Bahamut's built-in host. For external options, Imgur is essentially the only reliable choice.
Cross-forum posting: If you need the same image across multiple forums, Imgur currently has the best cross-forum compatibility — PTT, Dcard, and Bahamut all render Imgur direct links correctly. lpic.cc direct links also work on PTT and Dcard, but note that lpic.cc image links have an expiration mechanism (default 30 days, with a permanent option available) — verify the retention period meets your needs. For Bahamut, external host options are limited due to the whitelist.
FAQ
Why do Imgur links sometimes expand on PTT and sometimes not?
The most common cause is using the wrong link format. Imgur has two link types: https://imgur.com/abc (share page) and https://i.imgur.com/abc.jpg (direct link). PTT only recognizes direct link format. Additionally, if Imgur itself is temporarily down (DDoS attacks, server maintenance), images may fail to display temporarily.
What does Dcard's og:image preview mean?
Think of og:image as a webpage's "profile photo." Every webpage can designate a representative image, and when you share that page's link on social media or forums, the platform automatically displays this image as a preview. Dcard uses exactly this mechanism — it reads the og:image from whatever link you paste and renders it as a preview card.
Which image hosts work on Bahamut? Why are so many blocked?
Bahamut uses a whitelist system to filter image sources, primarily to prevent malicious links and inappropriate content. The most reliable choices are Bahamut's built-in host and Imgur. Other hosts may fail to display even with correct link formats, simply because they're not whitelisted.
Do forums compress images after upload?
Dcard's built-in upload compresses large images. Bahamut's built-in host also compresses. If you use external hosts (like Imgur or ImgBB), compression depends on the host itself — the forum doesn't apply additional compression. If image quality matters to you, upload to an external host first and then paste the link into the forum.
Is there one image host that works on every forum?
As things stand, Imgur has the best cross-forum compatibility — all three forums (PTT, Dcard, Bahamut) correctly display Imgur direct-link images. Just remember to always use the i.imgur.com direct link format.