AI Character Cards Explained: PNG, JSON & Tavern Cards (2026)

A character card is not merely a portrait. It is a structured package that can contain the character’s name, description, scenario, greeting, dialogue examples and other instructions. The image may be visible while the data remains embedded inside it, which is why renaming a card PNG to JPG can destroy more than image quality.

This reference separates the specification, the container and the platform importer. Those three layers explain why a valid card can still fail on a particular service.

Card anatomy: what the fields actually do

The widely used V2 specification wraps data in a versioned object and adds creator notes, system prompt, post-history instructions, alternate greetings, tags, creator metadata, extensions and an optional character book. Creator notes are for humans and should not silently become prompt instructions.

PNG, JSON and Tavern card are not synonyms

A normal PNG is not automatically a character card. A screenshot of a character is also not exportable profile data.

Read a card safely before importing

1. Duplicate the original file and inspect the copy.
2. Confirm the extension matches the actual file type.
3. Open JSON as text and identify the specification version.
4. Search for private names, API keys, URLs, hidden notes and unwanted instructions.
5. Review greetings, example dialogue, system prompt and post-history instructions separately.
6. Treat unknown extension fields as data to preserve, not commands to execute.
7. Scan files obtained from strangers before opening them in third-party tools.

Do not upload a private card to a public converter merely to see its contents. A local inspection path is safer when the card contains personal writing.

Compatibility is a mapping problem

An importer must map source fields into destination fields. If the destination has no alternate-greeting field, those greetings may be dropped. If it has no character-book support, lore entries may need manual reconstruction. If it applies its own system prompt, the card’s prompt can be ignored or merged differently.

Run a small acceptance test: name recognition, opening message, voice consistency, scenario facts, one example-dialogue behavior and one lore trigger. The SillyTavern character card import guide covers a concrete import workflow.

A clean migration workflow

Inventory

Record filename, card version, creator, license or sharing permission, avatar source and whether the card contains private edits. A folder full of unnamed PNG files is not a backup strategy.

Normalize

Keep one untouched original, one readable JSON copy when possible and one destination-specific working copy. Fix encoding and malformed fields without rewriting the character’s voice.

Test

Import one card, start a fresh conversation and run the six checks above. Only then repeat the mapping for the rest of the library. Use the character creation guide when a destination requires manual field entry.

Document

Write down which fields were preserved, transformed or dropped. This short migration note prevents future edits from being mistaken for original creator data.

Quality checklist for creators

• The first message contains place, action and a reply opportunity.
• Example dialogue demonstrates voice instead of narrating rules.
• Description and personality do not repeat the same adjectives.
• Scenario leaves multiple possible directions.
• Creator notes explain use without leaking into the prompt.
• Tags describe discovery and are not treated as behavioral instructions.
• Shared images and text are yours to distribute or appropriately licensed.

To study how a compact identity becomes a playable role, use the roleplay character ideas guide. To experience finished profiles without handling files, browse LumiChat Discover.

FAQ

Is every character card a PNG?

No. Cards can be distributed as readable JSON or as PNG files with embedded data, among other platform-specific forms.

Can I turn any portrait into a card?

Not automatically. A card needs structured character data, not just pixels.

Why does a card import without its avatar?

The destination may read JSON fields but not the image container, or the link to the image may be missing.

What is the difference between V1 and V2?

V2 adds a versioned envelope and more fields, including alternate greetings, creator metadata, extensions and character-book support.

Are cards safe to share?

Only after checking hidden data, private notes, personal identifiers and content rights.

Why does the same card behave differently across apps?

Models, prompt templates, supported fields and context handling differ even when both apps accept the file.