What's the fastest way to get started with an image API?

Test with curl first
Don't write code yet. Use curl to make one API call with your key. This confirms the endpoint URL, authentication method, and basic response format. Document the exact command that works.
Minimal code next
Write a simple script in your language of choice that replicates your curl command. Use a standard HTTP library (requests in Python, fetch in JavaScript, curl in Bash). Print the full response. Run it once.
Then add structure
Handle errors: check status codes, parse error messages, log them. Add a timeout. Extract the image URL or data from the response. Download and save the image. Now you have a working foundation.
Avoid early complexity
Don't optimize, cache, or parallelize first. Don't build a full client library. Make one working call, understand the response structure, then improve incrementally. This prevents wasting time on features you don't actually need.