Is the image loaded via CURL if -o is not specified?

Question

linux

I can not understand and find the answer

Is the picture loaded via CURL if you do not specify the output -o ?

The case is that I check pictures using curl through proxies that are billed for traffic.
To reduce the amount of traffic, you can only download headers, but not a picture.

So I can’t understand if the picture is being loaded and simply not saved anywhere (accordingly, the proxy will take into account the weight of the picture and write off the money) or the connection is generally terminated when trying to download the stream if you don’t specify the output -o

Thank you

Answer 1

To download only headers, do not skip -o, but specify -I
if you do not specify -o, it is assumed that curl will download directly to the console

-o, --output <file> Write to file instead of stdout