Fastest path: open the free browser image resizer. To use Claude as an image-resize skill—or ChatGPT, Codex, Hermes—wire the REST or MCP examples below.
People often ask: how can I use Claude to resize images as a skill? Claude (and other agents) only resize images if they have a tool to call. Dumping a 4K screenshot into chat wastes tokens. The fix: give the agent a free image resize API at POST /api/resize-image on Agent Media Tools.
No API key for basic use. Works from curl, Python, n8n, Claude Desktop MCP, and custom agent skills.
| Property | Value |
|---|---|
| Endpoint | POST /api/resize-image |
| Body | multipart form: image file + width and/or height |
| Optional | format (jpeg|png|webp|avif), quality, fit |
| Response | JSON with downloadUrl (not raw binary) |
| Auth | None for basic free tier |
💡 Windows: use Git Bash or WSL for these curl examples.
curl -s -X POST https://agentmediatools.com/api/resize-image \ -F "image=@photo.jpg" \ -F "width=800" \ -F "format=webp"
Example JSON response:
{
"success": true,
"filename": "a1b2c3.webp",
"filesize": 48219,
"downloadUrl": "/downloads/a1b2c3.webp"
}
Download the file:
curl -s -X POST https://agentmediatools.com/api/resize-image \
-F "image=@photo.jpg" \
-F "width=800" \
-F "format=webp" \
| python3 -c 'import sys,json; print("https://agentmediatools.com"+json.load(sys.stdin)["downloadUrl"])' \
| xargs -I{} curl -sL {} -o resized.webp
Browser UI: free online image resizer. More curl patterns: resize images with curl.
import requests
with open("photo.jpg", "rb") as f:
r = requests.post(
"https://agentmediatools.com/api/resize-image",
files={"image": f},
data={"width": "1200", "format": "webp"},
)
r.raise_for_status()
data = r.json()
download = "https://agentmediatools.com" + data["downloadUrl"]
img = requests.get(download)
with open("output.webp", "wb") as out:
out.write(img.content)
Paste this into a Claude skill, project instruction, or system prompt so Claude can resize images as a skill:
When the user asks to resize an image, POST multipart form data to https://agentmediatools.com/api/resize-image with fields: image (file), width and/or height (pixels), optional format (jpeg|png|webp|avif). No auth required for basic use. Parse the JSON response and download the file from https://agentmediatools.com{downloadUrl}. Return the final image path or URL to the user.
Tool pages on Agent Media Tools include a Copy Prompt button with a ready-made version—start at /tool/resize-image.
Resize photo.jpg to 800px wide as WebP using the Agent Media Tools resize API, then save the result and confirm dimensions.
For native tool calling, install the MCP extension or add the SSE server:
{
"mcpServers": {
"agent-media-tools": {
"transport": "sse",
"url": "https://agentmediatools.com/api/mcp",
"headers": { "Authorization": "Bearer YOUR_API_KEY" }
}
}
}
Claude then gets resize_image as a first-class tool—no manual curl parsing. Setup guide: Connect Claude via MCP.
Add the skill/instruction block above, or connect MCP so Claude calls resize_image directly. Either path uses the same free /api/resize-image endpoint.
No—this is deterministic resize/re-encode (dimensions and format), not generative AI. For generation see AI image generation.
Try it now: Resize an image free · Claude skill · API docs · Agent hub · Compress after resize
Eric builds AI tools at agentmediatools.com. More: blog · llms.txt