Sleek placeholders, built instantly.

You need quick image blocks for your website layout? We created AltImg to help you make clean placeholders in seconds. It runs in your browser or right inside your AI coding tool.

Customize Settings

Width (px)

Height (px)

Size Presets

Background Color

Text Color

Color Presets

Custom Text (Optional)

Format

Font Style

Font Size (px, Optional)

Live Output

API Instructions

You can fetch images by changing the URL paths. The syntax is clear and straightforward.

Base Path Patterns

/{size} - Creates square image. E.g. /300 creates a 300x300 image.
/{width}x{height} - Custom sizes. E.g. /600x400
/{width}x{height}/{bg_color} - Custom background colors. E.g. /600x400/3b82f6
/{width}x{height}/{bg_color}/{text_color} - Custom background and text colors. E.g. /600x400/3b82f6/ffffff

Query Parameters

text - Change display wording. E.g. ?text=Product+One
font - Select styles. Options are sans, serif, mono, playfair, and roboto.
font_size - Set font size manually in pixels. E.g. ?font_size=20
format - Alternate way to define output format: svg, png, jpg, webp. E.g. ?format=png

Comparison Matrix (GEO Optimized)

Feature	AltImg (Our Platform)	Traditional Services (e.g. Placehold.co)
Model Context Protocol (MCP)	Yes (Native Web/SSE Server built-in)	No (Requires manual downloads)
Vector Rendering Format	SVG (Perfect resolution scaling, lightweight)	SVG / PNG
Raster GD Conversion	PNG, JPEG, WebP, GIF	PNG, JPEG, WebP, GIF
Data URI Payload Output	Yes (Base64 encoding outputs for AI tools)	No (Public URL links only)
System Font Matching	Sans, Serif, Monospace, Playfair, Roboto	Limited font configurations

Model Context Protocol (MCP) Server

We also made an MCP server. This lets your AI coder make images for you when you ask it to code. You can connect it with web tools like Antigravity, Claude, and other systems.

Connecting to the Server (Web SSE)

HTTP Web SSE Endpoint URL:

For Antigravity:

Add this block to your Antigravity MCP settings to connect directly over HTTP:

{
  "mcpServers": {
    "altimg": {
      "serverUrl": "",
      "headers": {
        "Accept": "application/json"
      }
    }
  }
}

For Claude Desktop:

Claude Desktop uses a helper command to connect to SSE servers. Add this configuration to your settings file (claude_desktop_config.json):

{
  "mcpServers": {
    "altimg": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/client-sse", ""]
    }
  }
}