The RulePix preset
RulePix creates a 600 × 600 JPEG and searches for the highest quality result at or below 240 KB. That is the smallest published acceptable square dimension and works well as a predictable upload target.
Technical fit is not photo acceptance
The file also needs the correct colour, composition, background, expression, lighting, and recent likeness. Do not digitally enhance or alter your appearance. A Department of State employee makes the final acceptance decision.
Use the official source
Requirements can change. Review the current US Department of State digital image requirements before submitting.