Raster images are made of pixels and lose quality when scaled up, while vector images use mathematical shapes and scale infinitely without quality loss.
Raster (bitmap) images store visual information as a grid of colored pixels. Each pixel has a fixed color value, and the image has a fixed resolution (e.g., 1920x1080). Scaling a raster image up beyond its native resolution results in visible blurriness or pixelation. Common raster formats include JPG, PNG, WebP, GIF, and TIFF. Vector images, by contrast, store visual information as mathematical descriptions of shapes, paths, curves, and text. Because they are resolution-independent, vectors can be scaled to any size — from an icon to a building wrap — without losing sharpness. SVG, AI (Adobe Illustrator), and EPS are common vector formats. Choosing between the two depends on the content: photographs and complex imagery require raster, while logos, icons, and geometric illustrations are best as vectors.
SVG (Scalable Vector Graphics) is an XML-based vector image format that scales to any size without losing quality, ideal for logos and icons.
DPI (dots per inch) measures print resolution, while PPI (pixels per inch) measures screen resolution — they are related but not interchangeable.
Image transparency allows parts of an image to be fully or partially see-through using an alpha channel, essential for overlays and compositing.
Lossless compression reduces file size without discarding any data, allowing the original file to be perfectly reconstructed from the compressed version.