Pixel
A pixel is the smallest addressable picture element in a raster image or digital display representation.
Raster image dimensions are commonly stated in pixels. A pixel stores color or channel values and does not correspond to one fixed physical size across all screens or print outputs.
The smallest addressable unit in a raster image
Raster image dimensions are commonly stated in pixels. A pixel stores color or channel values and does not correspond to one fixed physical size across all screens or print outputs. In practical terms, Pixel belongs to the visual-production layer. Knowing that layer is important because it tells you what the term can change, what it cannot change, and where to look when something behaves unexpectedly.
Reading a 1200 × 800 image as a pixel grid
A 1200 × 800 image contains a grid 1200 pixels wide and 800 pixels high.
Where image pixels differ from CSS pixels
You do not need to memorize the term in isolation. It becomes useful when you can recognize it in the tool, browser, file or conversation where the concept is doing real work.
A Pixel is not a universal physical size
A pixel is the smallest addressable picture element in a raster image or digital display representation. By contrast, Resolution describes the amount or density of image detail represented in a digital or printed output context. The two can appear in the same project, but they describe different parts of the work and should not be used as interchangeable labels.
The mistake: mixing device, CSS and image pixels
The common mistake is to use Pixel as if it also meant Resolution. That blurs two separate decisions and usually sends troubleshooting in the wrong direction. A better test is practical: CSS pixels, device pixels and image pixels can represent different scales, especially on high-density screens.
Why scale depends on context
In day-to-day work, Pixel matters when the concept needs to be identified precisely instead of being grouped with a nearby term. The practical value is not the vocabulary itself; it is being able to identify the right control, file, setting or decision when the concept becomes relevant.
A 1200 × 800 image contains a grid 1200 pixels wide and 800 pixels high. That example is useful because it turns the definition into something you can recognize, test and discuss with other people working on the same project.
Related terms worth learning next
Sources and further reading
Use these references when you need documentation-level detail, specifications or product-specific behavior beyond the plain-English explanation above.