Disclosure: I work on Passlens, a browser-first passport and ID photo maker. This post is about the product decisions behind that workflow, not a neutral review of every tool in the space.
A passport photo looks simple until you try to make one that an upload form will actually accept. It is a headshot, yes, but it is also a small chain of constraints: physical size, pixel size, background, head position, print scale, and whatever the destination country's portal decides to reject that week.
That is why generic photo editors feel slightly wrong for this job. They can crop. They can resize. They can export. The hard part is not any one of those actions. The hard part is keeping all of them tied to the document rule the user picked.
The unit problem
For developers, document photos are awkward because two units matter at the same time.
