# Codex Imagegen > Image generation with Codex - Skill: `rohitmenonhart-xhunter/codex-imagegen` (Agent Skill, multi-file: 3 files) - Install (CLI): `npx skillmds@latest add rohitmenonhart-xhunter/codex-imagegen` - Raw SKILL.md: https://api.skillmd.com/api/skills/rohitmenonhart-xhunter/codex-imagegen/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: rohitmenonhart-xhunter (https://skillmd.com/u/rohitmenonhart-xhunter) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/rohitmenonhart-xhunter/codex-imagegen --- # Image generation with Codex Codex (OpenAI's coding agent) carries an image-generation tool. Driven non-interactively with `codex exec`, it turns a written brief into a PNG — with a transparent background when asked — and can save it straight into the project. This skill is the reliable way to do that from a Claude session. ## 1. Run it ```bash ~/.claude/skills/codex-imagegen/scripts/imagegen.sh "" ``` The script finds a working `codex` (see § 5), runs it in `` with a workspace-write sandbox, tells it to use its image generation tool and copy the result to ``, then verifies the file: mode, pixel size, share of fully transparent pixels. Expect 1–2 minutes and roughly 20–35 K Codex tokens per image. Generate several images in parallel by running the script several times at once (separate calls) — each is independent. ## 2. Write the brief (this is where the quality comes from) Say all of these, in this order, in plain prose: 1. **What** — the subject, its pose/composition, what it is doing. One scene per image. 2. **Style** — e.g. "editorial hand-inked illustration: loose confident ink outlines, flat colours, small hatching for texture", or "flat vector icon, 2 px strokes, rounded corners", or "soft 3D clay render". Name a public reference if it helps ("like the whimsical illustrations on the Whereby website"). 3. **Palette** — exact hex values for the two to four colours that matter, and what each is used for. 4. **Background** — "transparent background (alpha)" for cut-outs; otherwise the exact colour. Add "no ground, no shadow, no text, no border, no watermark". 5. **Size and composition** — the aspect and pixel size (1024×1024, 1536×1024, 1024×1536), and where the empty space should be ("scene in the lower-right quadrant, empty transparent space above and to the left, so it can sit in a page corner"). 6. **The hand-off** — "save it into this directory as `.png`; reply with only the absolute path and the pixel size". The script adds this line for you. Example brief that produced a good result: > Two graceful geese in flight, one slightly ahead of the other, drawn as an editorial hand-inked > illustration: loose confident ink outlines, flat warm coral-orange (#E8794E) bodies with a lighter peach > underside, small dark teal (#1E5C4B) beaks, legs and eye dots, tiny hatching for feather texture. > Transparent background (alpha), no ground, no shadow, no text, no border. Wide landscape image about > 1536x1024, birds flying left-to-right across the upper two thirds with generous empty transparent margins. ## 3. After generation - **Look at it.** Read the PNG (the Read tool renders images). Transparent areas show as black in that preview — that is the viewer, not the file. Judge composition, palette, edges. - **Check the numbers** the script prints: `RGBA` and a high "transparent %" for cut-outs; if the share of transparent pixels is 0 %, the model painted a background — regenerate with "transparent background (alpha)" earlier and more emphatically in the brief. - **Edges**: transparent images come with a soft feathered halo of partial alpha. Invisible on pale backgrounds, visible on dark ones. For a dark page, ask for "hard clean edges, no glow" or place the image on a matching dark colour. - **Size for the web** with `scripts/png_check.py --max-width 1200` (LANCZOS downscale, keeps the original in `src/`). 1–1.7 MB originals become 150–900 KB. - **Keep the briefs** beside the images (`PROMPTS.md` in the art folder) so the next person can regenerate in the same style when the palette changes. - **Wire it in** with a plain `` (`alt=""`, `aria-hidden` for decoration; `loading="lazy"` below the fold) or the framework's image component; position with CSS; check on a screenshot at desktop and phone widths. ## 4. Good uses, and limits Good: decorative illustrations, hero art, empty-state pictures, icons and logos to iterate on, textures, character vignettes, product-style renders, social cards. Ask for *one* subject per image; compose in CSS. Limits: text inside images is unreliable — keep words out and set them in HTML; exact brand logos of other companies will not (and should not) be reproduced; photorealistic people are not for decoration; every run is a fresh draw, so ask for the same palette and style words each time to keep a set consistent. Do not generate anything that imitates a real person or organisation. ## 5. Finding a working Codex The script tries, in order: `codex` on `PATH`, `/Applications/ChatGPT.app/Contents/Resources/codex`, `~/.codex/plugins/.plugin-appserver/codex`. An npm-global `codex` can be a broken wrapper whose native binary is missing (`spawn … ENOENT`); the ChatGPT-app copy is complete. Auth is whatever `codex login` set up (`~/.codex/auth.json`); no API key is needed. Generated files are also kept by Codex under `~/.codex/generated_images//`. Override the binary with `CODEX_BIN=/path/to/codex`. If no Codex is available: say so and offer the alternative (an image-generation API with a key the user provides), do not silently fall back to hand-drawn SVG.