What size photos are required for a one-year extension application in Thailand?

When applying for a one-year extension in Thailand, the photo size required is 2-4cm x 6cm, which may be larger than a typical passport photo. However, local photo shops are generally familiar with this requirement, and it's suggested to inform them the photos are for immigration purposes. The size is also indicated on the back of the TM7 application form, and concerns about strictness regarding the size are minimal as photo shops are accustomed to these specifications.