Gemini Imagegen

gemini-imagegen

Claude cannot generate raster images. Gemini sessions launched through the agy (Antigravity CLI) have a generate_image tool that can — this skill dispatches an agy job that generates the image and saves it to a file you specify.

Verified against agy 1.0.15 (model Gemini 3.1 Pro (High), tool name generate_image). Re-check agy --help if flags seem wrong.

Step 0 — Preflight

1. command -v agy — if missing, stop and tell the user to install the

Antigravity CLI (https://antigravity.google).

1. Decide the absolute output path(s) for the image(s). agy --print

sessions do not run in your invocation cwd, so relative paths land in the wrong place — always pass absolute paths in the prompt and --add-dir the destination directory.

Step 1 — Write the image prompt

Be specific — the quality of the image tracks the prompt. Include:

• Subject — what the image shows.
• Style — photo, flat illustration, 3D render, watercolor, pixel art,

logo mark, etc.

• Composition — framing, background, negative space.
• Colors / mood — palette, lighting.
• Intended use — favicon, hero banner, OG card — so the model picks a

sensible aspect ratio and level of detail.

For editing an existing image (restyle, variation, background removal), give the absolute path of the source image in the prompt, --add-dir its directory too, and ask Gemini to load it before generating the edited version.

Step 2 — Dispatch

One image (verified command shape — adapt prompt and paths):

agy --print "Use your generate_image tool to create: . Save the final image to /abs/path/out.png. When it is saved, print IMAGE_OK followed by the file path. If you cannot generate images, print IMAGE_UNSUPPORTED and stop." \
  --model "Gemini 3.1 Pro (High)" \
  --print-timeout 5m \
  --add-dir /abs/path \
  --dangerously-skip-permissions --sandbox

• --dangerously-skip-permissions --sandbox lets the job write the file

without an approval TTY (there is none in --print mode). If the user runs you in review mode and objects to auto-approval, ask before dispatching.

• Multiple images: dispatch them in parallel, one agy job per image —

either background several of the above commands, or reuse the gemini-swarm dispatcher (scripts/dispatch.sh) with one NN-slug.prompt.md per image (MODEL: Gemini 3.1 Pro (High) header). Never generate sequentially.

Step 3 — Verify and deliver

1. Check the output: file exists, non-zero size, IMAGE_OK in stdout.
2. Look at the image (read/view the file) — confirm it actually matches

the request before claiming success.

1. Wrong or off-brief result → refine the prompt (state what to change) and

re-dispatch; for small revisions, include the previous image as a source to edit.

1. Deliver: send/show the file to the user, or wire it into the project

(HTML ``, README, app asset) if that was the task.

Common mistakes

| Mistake | Fix | |---------|-----| | Relative output path | agy print jobs don't run in your cwd — absolute paths only, plus --add-dir. | | Claiming success from exit code alone | View the image; models sometimes save a wrong or blank file. | | Generating N images in one sequential session | One parallel agy job per image. | | Trying to generate the image yourself (SVG "art", ASCII, base64) when the user wanted a real image | That's the failure this skill exists to prevent — dispatch to Gemini. | | Telling the user "I can't generate images" | You can't, but Gemini via agy can. Use this skill instead of refusing. |

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Vallykrie
• Source: Vallykrie/gemini-swarm-skill
• License: MIT
• Homepage: https://github.com/Vallykrie/gemini-swarm-skill#readme

Install and usage instructions live in the source repository linked above.