All APIs have a default timeout of 300 sec (5 mins).
Why my request timeout at 60 sec instead of 300 sec?
Some programming language / command line tools have a default HTTP timeout of 60 sec. So although FormX server only terminate the request after 5 minutes, the client side (your application) may terminate it in 60 sec. You will need to change that.
If your requests are taking too long, consider lowering the image size, check out Image Upload Best Practice