1. A processor-implemented method for authorizing human access to complete an online transaction for a service over the Internet, comprising: a) detecting a request to enter information for the service, in response to the detection, i) identifying a first image for display at a receiver device, the first image defined to cover a display portion of a screen of the receiver device; ii) identifying a second image with a detectable trait, the second image configured for display over the first image; iii) executing a first delta-based analyzer to monitor changes of the first image; iv) executing a second delta-based analyzer to monitor changes of the second image, the changes of the second image include changes to the detectable trait; v) combining the changes to the first image and the second image, the changes to the first and the second images being independently adjustable to a respective first and second display settings; b) transmitting the combined changes of the first and the second images to the receiver device for display; c) transmitting a query regarding the detectable trait of the second image to the receiver device; d) receiving a response from a user to the query at the receiver device; and e) enabling user input of the information for the service at the receiver device when the response to the query is determined to be successful.