concept-to-image

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Turn any concept, idea, or description into a polished static HTML visual, then export it as a PNG or SVG image file. Use this skill when the user explicitly needs an image file output (PNG or SVG). This includes: concept diagrams, flowcharts, comparison charts, process visuals, educational diagrams, social media graphics, data visualizations, posters, cards, badges, icons, logo sketches, or any "make me an image of X" request achievable with HTML/CSS/SVG rather than photographic AI generation. Also trigger when the user has an existing HTML visual and wants to export/convert it to PNG or SVG. Trigger phrases: "create an image of", "export as PNG", "save as SVG", "concept to image", "turn this into an image", "screenshot this HTML", "design a graphic for export". For interactive HTML visuals opened in a browser, use static-web-artifacts-builder instead.

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NPX Install

npx skill4agent add mathews-tom/armory concept-to-image

Tags

Translated version includes tags in frontmatter

Concept to Image

Creates polished visuals from concepts using HTML/CSS/SVG as a refineable intermediate, then exports to PNG or SVG.

Reference Files

FilePurpose
references/design-guide.md
Design patterns, anti-patterns, color palettes, typography choices, layout examples
scripts/render_to_image.py
Playwright-based export script — takes HTML in, PNG or SVG out
assets/template.html
Base HTML template with
.canvas
container and CSS custom properties pre-configured

Why HTML as intermediate

HTML is the refineable layer between idea and image. Unlike direct canvas rendering, the user can see the HTML artifact, request changes ("make the title bigger", "swap the colors", "add a third column"), and only export once satisfied. This makes the workflow iterative and controllable.

Workflow

text
Concept → HTML artifact (view + refine) → PNG or SVG export
  1. Interpret the user's concept — determine what kind of visual best fits (diagram, infographic, card, chart, etc.)
  2. Design a self-contained HTML file using inline CSS and inline SVG — zero external dependencies
  3. Present the HTML as an artifact so the user can preview and request refinements
  4. Iterate on the HTML based on user feedback (colors, layout, content, sizing)
  5. Export to PNG and/or SVG when the user is satisfied, using
    scripts/render_to_image.py

Step 1: Interpret the concept

Determine the best visual format:
User intentVisual formatApproach
Explain a process/flowFlowchart or pipeline diagramSVG paths + boxes
Compare itemsSide-by-side or matrixCSS Grid
Show hierarchyTree or layered diagramNested containers + SVG connectors
Present dataChart or infographicSVG shapes + data labels
Social/marketing graphicCard or posterTypography-forward HTML/CSS
Icon, logo, badgeCompact symbolPure SVG
Educational conceptAnnotated diagramSVG + positioned labels

Step 2: Design the HTML

Read
references/design-guide.md
for detailed design patterns and anti-patterns.
Core rules:
  • Single file, self-contained: All CSS inline in
    <style>
    , all graphics as inline
    <svg>
    . No external resources.
  • Fixed viewport: Set explicit
    width
    and
    height
    on the root container matching the intended export size. This is critical — Playwright screenshots the element at this exact size.
  • Anti-AI-slop: Avoid centered-everything layouts, purple gradients, uniform rounded corners, and Inter/system font defaults. See design guide for alternatives.
  • SVG-first for shapes: Use inline SVG for icons, connectors, shapes, and any element that should scale cleanly. CSS for layout and typography.
  • Color with intention: 3-4 hues max + neutrals. Define as CSS custom properties. Every color encodes meaning.
  • Start from the template: Use
    assets/template.html
    as the base structure.

Sizing guidelines

Use caseRecommended size
Social media graphic1200×630
Infographic (portrait)800×1200
Presentation slide1920×1080
Square post1080×1080
Icon/badge256×256 or 512×512
Wide diagram1600×900
Set the
.canvas
container to the chosen size. The export script captures this element.

Step 3: Present and iterate

Present the HTML file to the user. They'll see it rendered as an artifact. Common refinement requests:
  • Color/theme changes → update CSS custom properties
  • Layout adjustments → modify grid/flexbox
  • Content changes → edit text/SVG elements
  • Size changes → update
    .canvas
    dimensions
Each iteration is a quick HTML edit, not a full re-render. This is the key advantage over direct image generation.

Step 4: Export to image

Once the user is satisfied, run the export script:
bash
python3 scripts/render_to_image.py <input.html> <output.png|.svg> [--width 1200] [--height 630] [--scale 2] [--selector ".canvas"]

Parameters

ParamDefaultDescription
input
(required)Path to HTML file
output
(required)Output path. Extension determines format (.png or .svg)
--width
autoViewport width (overrides HTML-defined size)
--height
autoViewport height (overrides HTML-defined size)
--scale
2Device scale factor for PNG (2 = retina quality)
--selector
.canvas
CSS selector for the element to capture
--full-page
falseCapture the full page instead of a specific element

PNG export

Uses Playwright to launch headless Chromium and screenshot the
.canvas
element at the specified scale factor. Scale 2 produces retina-quality output (e.g., 1200×630 CSS pixels → 2400×1260 PNG).

SVG export

Two strategies, chosen automatically:
  1. SVG-native content: If the
    .canvas
    element contains a single root
    <svg>
    , extracts it directly as a clean SVG file. This produces a true vector SVG.
  2. HTML-based content: If the content is CSS/HTML-heavy, falls back to PNG export with a note that true SVG requires SVG-native design. The script will warn and suggest redesigning with SVG elements if vector output is needed.

Delivering the output

Present the output file to the user. Always deliver both the HTML (for future editing) and the image (final output).

Error Handling

ErrorCauseResolution
playwright
not found
Playwright package not installedRun
npx playwright install chromium
or
pip install playwright && playwright install chromium
Browser launch failureHeadless Chromium fails to startVerify
--headless
mode is supported; check available memory (Chromium needs ~200 MB)
.canvas
selector not found
HTML does not contain an element matching
.canvas
Verify
assets/template.html
was used as the base; check the root container has
class="canvas"
Render timeoutComplex HTML takes too long to render before screenshotIncrease the timeout via
--timeout
flag in the script, or simplify the HTML (reduce DOM depth, inline fewer SVGs)
SVG export falls back to PNG
.canvas
element contains HTML/CSS content, not a root SVG
See SVG export section; redesign with a single root
<svg>
if vector output is required

Limitations

  • Playwright + Chromium required — the export script cannot run without a working Chromium installation.
  • macOS and Linux only for headless browser export. Windows Subsystem for Linux works; native Windows Playwright may require separate setup.
  • SVG export is best-effort — complex HTML/CSS layouts fall back to PNG. True vector SVG requires a single root
    <svg>
    as the
    .canvas
    child.
  • Max viewport 4096×4096 — Chromium refuses screenshots larger than this. Use
    --scale
    to achieve higher effective resolution within this limit.
  • No animation support — exported images are static snapshots. CSS animations and JavaScript-driven transitions are frozen at their initial state.

Output Example

After a successful export, the script prints the output path and file stats:
text
Exported: concept-diagram.png
  Size:       2400 × 1260 px  (2× scale from 1200 × 630 canvas)
  File size:  ~180 KB
  Format:     PNG (RGBA)
Filename pattern follows whatever was passed as the output argument. Typical file sizes:
  • Simple diagrams (text + shapes): 80–200 KB
  • Dense infographics with gradients: 300–600 KB
  • Full 1920×1080 at 2× scale: 500 KB–1.5 MB

Design anti-patterns to avoid

These produce generic "AI-generated" looking output:
  • Centered everything with equal spacing
  • Purple/blue gradient backgrounds
  • Uniform border-radius on all elements
  • Generic icon libraries (use custom inline SVG)
  • System font stack without typographic intention
  • Drop shadows on everything
  • Low information density (too much whitespace)

Font handling

Since this environment has limited font access, use web-safe font stacks with intentional fallbacks:
  • Technical/mono:
    'Courier New', 'Consolas', monospace
  • Clean sans:
    'Helvetica Neue', 'Arial', sans-serif
  • Editorial serif:
    'Georgia', 'Times New Roman', serif
  • Display: Use SVG text with custom paths for display typography when needed