Digital Images and Graphics
Digital images are visual representations stored as data.
Raster vs Vector
Raster: pixel grids, photographic detail, lose quality on scaling. Vector: mathematical shapes, scale without loss, ideal for logos.
Resolution and Colour Depth
Resolution: width×height pixels. DPI for print (300 typical). Colour depth: 1-bit to 32-bit (true colour + alpha).
Colour Models
RGB (screens, additive), CMYK (print, subtractive), HSV/HSL (intuitive), YCbCr (video/JPEG).
Image Formats
JPEG (lossy, photos), PNG (lossless, transparency), GIF (animation), SVG (vector, web), TIFF, WebP.
Processing
Resizing, cropping, colour adjustment, filtering, compositing. Photoshop, GIMP, Inkscape.
Compression
Lossless (PNG) vs lossy (JPEG, DCT-based). Quality vs file size trade-off.
Summary
Digital images form the visual foundation of multimedia.