The safest starting point is the application itself: identify the document, the country, and whether the photo is being uploaded, printed or both.
Work from hard limits to soft judgments
File size and dimensions can usually be checked numerically. Face position, lighting and background need a visual review against the official examples.
Keep a copy of the version that failed
When troubleshooting, do not overwrite the previous file immediately. A simple filename such as passport-original.jpg, passport-size-fixed.jpg and passport-upload-version.jpg makes the workflow auditable and prevents accidental loss of the original.
When you need another version
Start again from the master rather than resizing the finished JPEG. Different applications can require different crops, dimensions or file limits, and a clean source makes the second output much easier.
Why two correct-looking photos can be different
Two portraits can show the same person and still be different deliverables because the receiving systems may measure the face or frame differently. A size conversion alone does not reconcile those differences.
Create each output from the clean master and label it for the destination.
Practical detail to carry forward
Save the rule with the file when the job is important. A screenshot or note of the size and upload limit can prevent a later re-edit when a portal changes its wording.
How to Fix a Blurry Passport Photo
Prepare the file, inspect it at full size and save the exact version that belongs to your application.