A headline plan price is not a total-cost comparison. Use one representative month, preserve every excluded meter, and test the product boundary before deciding. The five checks below are the same ones Keenpix uses for its source-dated calculator and comparison reviews. Save the inputs, official source URLs, response headers, and test date with the decision so a later pricing or cache-policy change can be audited instead of remembered.
1. Capture the workload before choosing units
Record delivered image GB after optimization, request count, source storage, unique generated variants, projects or sites, custom domains, delivery regions, source-change frequency, and cache hit behavior. Use a normal month and a peak month. Do not start by translating one vendor unit into another: a credit, transformation, cache read, worker, stored image, and delivered GB describe different work. If a required input is unavailable, label the resulting estimate partial instead of replacing it with zero.
2. Normalize the product boundary, not only the invoice
List what imgix includes that Keenpix does not and what your team would need to replace. That may include source storage, DAM workflows, video, a hosting platform, a bundled CDN, AI operations, upload widgets, support, or a self-hosted engine. Then list what sits outside each public price: transfer, requests, infrastructure, observability, additional domains, plan minimums, and operator time. A lower partial subtotal is not automatically a lower complete bill, and a broader platform can be worth paying for when you use its breadth.
3. Test cache and failure behavior
Run a representative URL set through both options. Measure a cold transform, a warm generated-variant hit, an edge hit, an expired source, an invalid signature, an unavailable origin, and a request above the usage allowance. Confirm which layer records billable usage and whether browser or customer-owned CDN hits reach it. Document cache keys, invalidation, stale behavior, retry limits, and the response users receive at a limit. Provider documentation is necessary, but a canary with your headers, URLs, and origins is the stronger acceptance test.
4. Price ownership and security work
Identify who owns origin allowlists, SSRF protection, signing keys, abuse controls, TLS, DNS, capacity, updates, vulnerability response, dashboards, logs, alerts, backups, incident response, and cost anomalies. A managed service moves some of those responsibilities to a vendor; a self-hosted or platform-native option may keep them with your existing team. Compare the architecture you will actually operate, including on-call and recovery expectations, rather than valuing engineering time at zero or assuming a managed boundary eliminates every integration task.
5. Define migration and rollback before the winner
Inventory production transformation options and save visual fixtures before translating URLs. Decide whether originals move, whether both services can read the same origin, how signatures and custom domains change, and how long old URLs must remain valid. Canary a measurable traffic slice and set acceptance thresholds for output dimensions, visual crops, content type, cache behavior, latency, errors, and projected cost. Keep the old path available until a complete traffic cycle passes. The right choice is the one that meets those thresholds and has a credible rollback, not the one with the longest feature column.
