Agent-Skills.md

Agent Skills: Sirv Dynamic Imaging API

Sirv dynamic imaging URL API for on-the-fly image transformation. Use when building image URLs with Sirv CDN, resizing images via URL parameters, adding watermarks/text overlays, cropping, applying filters, format conversion (WebP, AVIF), or any Sirv URL-based image manipulation. Covers 100+ URL parameters for scaling, cropping, effects, text, watermarks, frames, and optimization.

UncategorizedID: igorvaryvoda/image-optimization-skill/sirv-dynamic-imaging

Install this agent skill to your local

pnpm dlx add-skill https://github.com/IgorVaryvoda/image-optimization-skill/tree/HEAD/skills/sirv-dynamic-imaging

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skills/sirv-dynamic-imaging/SKILL.md

Skill Metadata

Name
sirv-dynamic-imaging
Description
Sirv dynamic imaging URL API for on-the-fly image transformation. Use when building image URLs with Sirv CDN, resizing images via URL parameters, adding watermarks/text overlays, cropping, applying filters, format conversion (WebP, AVIF), or any Sirv URL-based image manipulation. Covers 100+ URL parameters for scaling, cropping, effects, text, watermarks, frames, and optimization.

Sirv Dynamic Imaging API

Transform images on-the-fly by adding URL parameters.

Base URL: https://yourcdn.sirv.com/path/image.jpg?{options}

Prefer high-quality masters and delivery-time transformations. Sirv applies URL parameters before profile settings, and profile settings before the Default profile. Processing order is auto-crop, scale, crop, canvas, rotate, then other effects; URL parameter order does not change that order.

Official Sources First

Check current Sirv docs before changing parameter names, defaults, or fallback behavior:

  • https://sirv.com/help/articles/dynamic-imaging/
  • https://sirv.com/help/articles/dynamic-imaging/format/
  • https://sirv.com/help/articles/dynamic-imaging/crop/
  • https://sirv.com/help/articles/responsive-images-smv/

Quick Reference

Sizing

| Option | Example | Description | |--------|---------|-------------| | w | ?w=800 | Width (px or %) | | h | ?h=600 | Height (px or %) | | s | ?s=500 | Longest dimension | | thumbnail | ?thumbnail=200 | Square thumbnail | | scale.option | ?scale.option=fit | fit, fill, ignore, noup |

?w=800                    # 800px wide
?w=50%                    # 50% of original width
?w=800&h=600              # Specific dimensions
?w=800&scale.option=fit   # Fit within 800px (maintain aspect)
?w=800&scale.option=fill  # Fill 800px (may crop)

Cropping

| Option | Example | Description | |--------|---------|-------------| | cw, ch | ?cw=500&ch=300 | Crop width/height | | cx, cy | ?cx=100&cy=50 | Crop start position | | crop.type | ?crop.type=face | Auto-crop: trim, poi, face |

?cw=500&ch=300&cx=100&cy=50   # Manual crop
?crop.type=face&w=400          # Face detection crop
?crop.type=trim                # Trim whitespace

Format & Quality

| Option | Example | Description | |--------|---------|-------------| | format | ?format=optimal | jpg, png, webp, avif, optimal, original | | q | ?q=85 | JPEG/WebP quality 0-100; default is usually 80 | | subsampling | ?subsampling=4:2:0 | JPEG chroma subsampling |

?format=optimal             # Auto-select best format
?format=webp&q=80           # WebP at 80% quality
?format=avif                # AVIF format
?format=original            # Preserve original format

Prefer format=optimal or the account default for web delivery unless a fixed format is required. If forcing WebP/AVIF, verify the fallback behavior in current Sirv docs and rendered responses.

Effects

| Option | Range | Description | |--------|-------|-------------| | blur | 0-100 | Gaussian blur | | sharpen | 0-100 | Sharpen | | brightness | -100 to 100 | Brightness | | contrast | -100 to 100 | Contrast | | saturation | -100 to 100 | Saturation | | grayscale | true/false | Black & white | | rotate | -180 to 180 | Rotation degrees | | colortone | preset name | sepia, warm, cold, sunset... |

?blur=10                    # Light blur
?grayscale=true&contrast=20 # B&W with more contrast
?colortone=sepia            # Sepia effect
?rotate=90                  # Rotate 90 degrees

Text Overlay

?text=Hello%20World
?text=Hello&text.size=30%&text.color=white&text.position=southeast
?text=©%20Acme&text.font.family=Open%20Sans&text.opacity=50

Watermark

?watermark=/logo.png
?watermark=/logo.png&watermark.position=southeast&watermark.opacity=50
?watermark=/logo.png&watermark.scale.width=20%

Canvas & Frame

?canvas.width=1200&canvas.height=800&canvas.color=white
?frame.style=solid&frame.color=black&frame.width=10

Common Patterns

Responsive srcset

<img
  src="https://cdn.sirv.com/image.jpg?w=800&q=80"
  srcset="
    https://cdn.sirv.com/image.jpg?w=400&q=78 400w,
    https://cdn.sirv.com/image.jpg?w=800&q=80 800w,
    https://cdn.sirv.com/image.jpg?w=1200&q=82 1200w
  "
  sizes="(max-width: 600px) 100vw, 50vw"
  width="1200"
  height="800"
  alt="Description"
>

Modern format with fallback

<picture>
  <source srcset="https://cdn.sirv.com/image.jpg?format=avif" type="image/avif">
  <source srcset="https://cdn.sirv.com/image.jpg?format=webp" type="image/webp">
  <img src="https://cdn.sirv.com/image.jpg" alt="Description">
</picture>

Product thumbnail

?w=400&h=400&scale.option=fit&canvas.width=400&canvas.height=400&canvas.color=white

LCP hero

?w=1600&q=82&scale.option=noup

Pair with preconnect/preload, fetchpriority="high", explicit dimensions, and no lazy loading.

Watermarked download

?watermark=/logo.png&watermark.position=southeast&watermark.opacity=30&dl

When to Read Reference Files

  • Sizing & cropping (scale options, crop modes, canvas): See sizing.md
  • Effects & filters (color, blur, sharpen, colortone presets): See effects.md
  • Text & watermarks (fonts, positioning, styling): See overlays.md
  • Profiles & optimization (reusable presets, caching, formats): See profiles.md

Profiles

Save reusable option sets as JSON profiles in /Profiles/:

?profile=my-thumbnail

Profile example:

{
  "image": {
    "scale": {"width": 400},
    "format": "optimal",
    "quality": 80
  }
}

Use profiles for repeated recipes such as product cards, marketplace exports, watermarked downloads, and social previews. Keep one-off layout sizing in URL params.

Workflow

  1. Decide whether the transform is one-off markup, a reusable profile, or code that should use a helper/builder.
  2. Check the official docs for exact parameter names and value ranges.
  3. Preserve existing query params unless the task explicitly replaces them.
  4. Use format=optimal or account defaults for browser delivery unless a fixed format is required.
  5. Add or update assertions for final URL shape when the transform is business-critical.

Use ../sirv-media-viewer/SKILL.md instead when the change is about gallery behavior, zoom/spin/video/model/PDF viewing, thumbnails, fullscreen, mobile breakpoints, Sirv JS loading, viewer API/events, or SMV accessibility. Dynamic Imaging owns delivery transforms; Sirv Media Viewer owns the interactive presentation.

Red Flags

  • Hand-writing many repeated query strings instead of using a profile or helper.
  • Dropping existing query params, custom domains, signed URLs, or source URL behavior by accident.
  • Treating thumbnails, AI-source images, and final delivery URLs as the same transform contract.
  • Using scale.option=ignore unless distortion is explicitly desired.
  • Changing format, quality, crop, or upscaling defaults without visual or byte-size verification.

Verification

  • Confirm final URLs use documented parameter names and values.
  • Check content-type, content-length, and cache headers with curl -I.
  • Verify rendered dimensions are close to display size multiplied by DPR.
  • Compare desktop/mobile crops visually when using fill, poi, face, or manual crop params.
  • Confirm LCP images request early and below-fold images do not all load immediately.