If your native country is anything other than the US, Burma, or Liberia, then your passport photos are very likely measured in millimeters, not inches. This means that the drug stores and travel clubs either can't, or won't, be able to correctly provide the images your need.
When knowledge of the metric system is required, and every country has different size requirements, you really need to call someone who is an expert at foreign and international passport photos. Lucky for you, the most experienced and qualified foreign passport photographer in Florida, resides right here in Tampa.
Newsome's Studio of Photography, located in Carrollwood (North Tampa) at 10012 N. Dale Mabry Hwy, Suite 219 in Cypress Point Office Park (behind Starbucks, on the NW corner of Linebaugh and Dale Mabry Hwy), is Tampa's passport photo expert.
By appointment only... call 813-968-2810 and get it right the first time.