imagegen

imagegen is a skill for Codex from chenrui333/codex-docs. It costs 113 tokens per session (5,380 once invoked), scanned A, a copy of imagegen, MIT.

A guide for generating or editing bitmap images, such as illustrations, mockups, photos, textures, and transparent cutouts.

In plain words
What is it for?
Use it when a project needs new visual assets, edited images, UI mockups, or batches of generated images.
Why use it?
It explains which image-generation method to use and how to handle common cases such as transparent backgrounds.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: mentions Codex.

Good fit Use it when a project needs new visual assets, edited images, UI mockups, or batches of generated images.

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Install with agentmods
npx agentmods add skills/chenrui333/codex-docs/imagegen
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add chenrui333/codex-docs --skill imagegen
Clone the repo
git clone --depth 1 https://github.com/chenrui333/codex-docs

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for imagegen

README.md
[![agentmods](https://agentmods.dev/badge/skills/chenrui333/codex-docs/imagegen/github.svg)](https://agentmods.dev/skills/chenrui333/codex-docs/imagegen)
Your own site
<a href="https://agentmods.dev/skills/chenrui333/codex-docs/imagegen"><img src="https://agentmods.dev/badge/skills/chenrui333/codex-docs/imagegen/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for imagegen

Your own site · 80×15
<a href="https://agentmods.dev/skills/chenrui333/codex-docs/imagegen"><img src="https://agentmods.dev/badge/skills/chenrui333/codex-docs/imagegen.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 113 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,380 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 89% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00113 $0.05380
Opus 5.5 $0.00045 $0.02152
Sonnet 5.5 $0.00023 $0.01076
Haiku 4.5 $0.00011 $0.00538

Measured 6d ago against content hash 60bdec108b1e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

imagegen scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/image_gen.py, scripts/remove_chroma_key.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

89% identical to imagegen — 12 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

dot_codex/skills/dot_system/imagegen/SKILL.md · 324 lines

How it starts

The opening of the file, as written. The whole thing — 324 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Image Generation Skill

Generates or edits images for the current project (for example website assets, game assets, UI mockups, product mockups, wireframes, logo design, photorealistic images, or infographics).

Top-level modes and rules

This skill has exactly two top-level modes:

  • Default built-in tool mode (preferred): built-in image_gen tool for image generation, editing, and transparent-image requests. Does not require OPENAI_API_KEY.
  • Fallback CLI mode: scripts/image_gen.py CLI. Use when the user explicitly asks for or confirms the CLI/API/model path. Requires OPENAI_API_KEY.

Within CLI fallback, the CLI exposes three subcommands:

  • generate
  • edit
  • generate-batch

Rules:

  • Use the built-in image_gen tool by default for normal image generation and editing requests.
  • Do not switch to CLI fallback for ordinary quality, size, or file-path control.
  • For transparent images, ask built-in image_gen for a transparent background and preserve the generated alpha.
  • Never silently switch from built-in image_gen or CLI gpt-image-2 to CLI gpt-image-1.5; ask the user first unless they explicitly requested gpt-image-1.5.
  • The word batch by itself does not mean CLI fallback. If the user asks for many assets or says to batch-generate assets without explicitly asking for CLI/API/model controls, stay on the built-in path and issue one built-in call per requested asset or variant.
  • If the built-in tool fails or is unavailable, tell the user the CLI fallback exists and that it requires OPENAI_API_KEY. Proceed only if the user explicitly asks for that fallback.
  • If the user explicitly asks for CLI mode, use the bundled scripts/image_gen.py workflow. Do not create one-off SDK runners.
  • Never modify scripts/image_gen.py. If something is missing, ask the user before doing anything else.

Built-in save-path policy:

  • In built-in tool mode, Codex saves generated images under $CODEX_HOME/* by default.
  • Do not describe or rely on OS temp as the default built-in destination.
  • Do not describe or rely on a destination-path argument (if any) on the built-in image_gen tool. If a specific location is needed, generate first and then move or copy the selected output from $CODEX_HOME/generated_images/....
  • Save-path precedence in built-in mode:
    1. If the user names a destination, move or copy the selected output there.
    2. If the image is meant for the current project, move or copy the final selected image into the workspace before finishing.
    3. If the image is only for preview or brainstorming, render it inline; the underlying file can remain at the default $CODEX_HOME/* path.
  • Never leave a project-referenced asset only at the default $CODEX_HOME/* path.
  • Do not overwrite an existing asset unless the user explicitly asked for replacement; otherwise create a sibling versioned filename such as hero-v2.png or item-icon-edited.png.

Read the full file on GitHub · 324 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago Changed 60bdec108b1e
  2. 13d ago Changed 46e538ea44a2
  3. 14d ago Changed 7083b06745dd
  4. 15d ago Changed 37ccaa54ded9
  5. 17d ago Changed 2010781bf414
  6. 20d ago Changed 36f94512b0dc
  7. 22d ago Changed 13f01e02778d
  8. 23d ago Changed 1506c09047f1
  9. 24d ago Changed 7fe71b12ca6f
  10. 26d ago First seen · 324 lines · 113 tokens per session scan A ab7349be3f59

Subscribe to this mod's changes

imagegen is a skill published in the GitHub repository chenrui333/codex-docs (5 stars, last pushed yesterday), licensed MIT. It adds 113 tokens to every session and 5,380 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 89% identical to imagegen, differing in 12 lines, and is treated as a copy.