What is the smallest identifiable element that composes an image on a computer screen?

The smallest identifiable element that composes an image on a computer screen is a pixel. A pixel, short for "picture element," represents the most basic unit of a digital image or display. Each pixel contains color information and together, a grid of pixels creates the full image that you see on-screen.

In the context of digital imaging, a pixel can vary in size and color depth, depending on the display technology and the image resolution. For example, a higher resolution image has more pixels packed into the same area, resulting in a finer level of detail.

The other terms relate to different aspects of digital imaging and computing. A byte refers to a unit of digital information that typically consists of eight bits and is used to represent data values, including the color information for pixels but is not itself the smallest visual component of an image. A vector refers to a method of graphics representation that uses mathematical equations to create art, such as lines and shapes, which can be scaled without loss of quality and does not consist of pixels. A bitmap is a type of image file format that stores images as an array of pixels but does not refer to the pixels themselves.

Thus, the pixel is undeniably the essential building block of images displayed on computer screens.