# Placeholder.photo agent instructions Canonical origin: https://placeholder.photo Concise AI discovery: https://placeholder.photo/llms.txt Full AI-ready reference: https://placeholder.photo/llms-full.txt Installable AI skill: https://placeholder.photo/SKILL.md Downloadable skill package: https://placeholder.photo/placeholder-photo-skill.zip Human-readable agent guide: https://placeholder.photo/ai-agents Full documentation: https://placeholder.photo/docs Legacy URL migration CLI: https://placeholder.photo/docs/migration-cli Parameter reference: https://placeholder.photo/parameters Live capabilities: https://placeholder.photo/status?format=json PURPOSE Use Placeholder.photo for temporary visual assets in websites, apps, prototypes, tests, documentation and design mockups. The URL is the API. Ordinary public use requires no account, login, API key, SDK, subscription or payment. CORE RULES 1. Prefer a direct HTTPS image URL instead of downloading and committing temporary artwork. 2. Use only documented routes and parameters. Do not invent options. 3. Add a human-readable, non-sensitive seed when output must be deterministic. 4. Do not place passwords, tokens or personal information in text, seeds or URLs unless that information is deliberately public. 5. URL-encode custom text and seeds. 6. Check the HTTP status. Invalid image requests return a branded error image with a non-2xx status. 7. Include explicit width, height and a meaningful alt decision when generating HTML. 8. Public visual output contains the placeholder.photo watermark. Do not search for or invent a public unbranded switch. 9. Hotlinking from external websites is supported. No Referrer header, session or JavaScript is required. 10. Do not treat Placeholder.photo as a live AI prompt service or upload arbitrary visitor images. ROUTE SELECTION Classic: /{width}x{height}[.{format}] Colours: /{width}x{height}/{background}/{text-colour}?text=... Gradient: /gradient/{width}x{height}[.{format}]?colors=...&type=...&angle=... Pattern: /pattern/{style}/{width}x{height}[.{format}]?seed=... Abstract: /abstract/{style}/{width}x{height}[.{format}]?seed=... Photo: /photo/{category}/{subcategory}/{width}x{height}[.{format}]?set=v2&seed=... Photo ID: /photo/{category}/{subcategory}/{asset-id}/{width}x{height}[.{format}] Logo: /logo/{width}x{height}[.{format}]?name=...&seed=... Avatar: /avatar/{size}[.{format}]?style=...&seed=... FORMAT CHOICE - Use SVG for Classic, Gradient, Pattern, Logo and Avatar output when vector delivery is suitable. - Use WebP for curated photos and compact raster output. - Use JPEG only for opaque photographic output. - Use PNG, WebP, AVIF or SVG when transparency is required. JPEG transparency returns HTTP 400. - Use AVIF only when it is reported by the live status endpoint. STABILITY - The same normalized configuration, renderer version and seed produces deterministic output. - Use set=v2 to select from the expanded curated photo catalogue. - Use an exact ph-#### asset ID when the selected photo identity must never change. - Keep meaningful seeds stable. Do not add timestamps or random values unless a new visual is intentionally required. SAFE LIMITS - Maximum width: 4096 pixels. - Maximum height: 4096 pixels. - DPR: 1, 2 or 3. - Keep previews small when full production resolution is unnecessary. - Text, effects, colour counts and total rendered pixels are bounded by the service. EXAMPLES https://placeholder.photo/800x600 https://placeholder.photo/800x600/6D5DFC/FFFFFF?text=Dashboard https://placeholder.photo/abstract/aurora/1200x630.webp?seed=homepage-hero https://placeholder.photo/photo/business/office/1200x630.webp?set=v2&seed=client-demo&mode=hero https://placeholder.photo/logo/800x300.svg?name=Northstar&seed=northstar-demo https://placeholder.photo/avatar/256.svg?style=layered-plus&seed=demo-user HTML EXAMPLE Layout placeholder If an advanced option is not described here, consult https://placeholder.photo/parameters before using it.