Lorem Picsum vs ReSmush.it

Lorem Picsum serves placeholder photos by encoding the size, and optionally a specific image ID or a seed, directly into the request URL — no signup or key required. Every photo comes from Unsplash's library, and query parameters can request a grayscale or blurred variant, a JPEG or WebP file extension, or a random cache-busting suffix for multiple images at one size. A companion /v2/list JSON endpoint returns the full photo catalog with author and dimension metadata for browsing before you hotlink.

ReSmush.it is a free, keyless image-optimization API — best known as the backend behind the ReSmush.it WordPress plugin — that accepts a source image URL and returns a JSON payload with the compressed image's URL plus original size, compressed size, and percent reduction. A live call against api.resmush.it needed no credentials and returned Access-Control-Allow-Origin: *, so it works directly from browser JavaScript. The plain http:// endpoint immediately redirects to https, so the service is https-only despite requiring no API key.