The inspiration came from my own visa application, where I was run around to get 2-inch and 3-inch photos. People who don't know Photoshop or image editing tools really can't figure this out.
I spent some time building this tool.
Simple workflow: Select country → Upload photo → Crop → Download
Supports passport photo specifications for over 10 countries including the US, China, and India
Generates 4x6 inch print-ready layouts, take it directly to the print shop to develop
Photos are processed locally, no uploads to servers.