In this paper, we present the design, fabrication and thermal simulation of smart 1024-element (32 x 32 pixels), monolithic, pyroelectric, functional electro-ceramic material-based infrared (IR) image sensors. A sol-gel-deposited PbZr0.4Ti0.6O3 (PZT) thin film was used as a pyroelectric material for the detector. We tailored the geometries and dimensions of the devices in designing the the image sensors with a smart material. The influence of a thermal isolator has been shown to significantly reduce heat loss to the device structure and environment. Introducing circular pixels instead of square ones has confirmed the ability to obtain an optimal design with a functional material for use in a smart image sensor, resulting in a maximal temperature change of 4 mK at a response frequency of 10 Hz.