For a visa to China, the photo must strictly comply with the requirements, so it is important to choose a reliable way to take it right away. In a photo studio, of course, it is easier - the photographer himself will adjust the shot to the required parameters, but this requires time and money. Online services are a good alternative, especially if you have a suitable shot. The main thing is to keep an eye on the lighting and background so that the result doesn't have to be redone.