Detecting image type from base64 string in PHP

Question

Is it possible to find out the type of an image encoded as a base64 String in PHP?

I have no method of accessing the original image file, just the encoded string. F

Answer 1

The way shown by @Marc B is the nicest.

Should FInfo not be available, the only other way I know is to store the data into a file, and run a getimagesize() on it.