Take screenshot alternative

Hey Guys

I have to download a picture which is present in a web portal , that image differs each time , its size varies each time , but it is present is same web portal

i tried take screenshot but its nt working , please tell me alternative , i cant use http request because its present in a secure web portal

Please tell solution

we would recommend to check if HTTP request will work when Authentication info will also be used for the call.

A bad way would be as an alternate an UiAutomation of right click save image as action

i tried by giving credentials in simple http section of http request its givng success response of login page but after that the particular page iam unable to download pic