PDF
Stands for Portable Document Format. Created by Adobe Systems in its software program Adobe Acrobat as a universal browser. Files can be downloaded via the web and viewed page by page, provided the user is computer has installed the necessary plug-in which can be downloaded from Adobe's own web site.
Pixel
Stands for one picture element (one dot on a computer monitor); commonly used as a unit of measurement.
PDF
Stands for Portable Document Format. Created by Adobe Systems in its software program Adobe Acrobat as a universal browser. Files can be downloaded via the web and viewed page by page, provided the user is computer has installed the necessary plug-in which can be downloaded from Adobe's own web site.
PNG
Stands for Portable Network Graphics format, and is generally pronounced "ping." PNG is used for lossless compression and displaying images on the web. The advantages of PNG is that it supports images with millions of colors and produces background transparency without jagged edges. The disadvantages are that PNG images will not show up on older browsers, and still can be comparatively larger in file size than GIFs.
PPI
Stands for pixels per inch. PPI specifies the resolution of an input device, such as a scanner, digital camera, or monitor. Web page resolution ranges from 72-96 pixels per inch. (For information on output device measurements see dpi.)