Pixel and Resolution

What is a pixel?
A pixel is the smallest part of a picture, they are arranged in a grid to make up a picture and each pixel is a different colour. The more pixels in the image, the bigger it is.

Image Resolution
Image resolution is the actual size of the image, usually measured in pixels, the most common image sizes are 800x600 and 1200x800.

Raster Image
Raster images are made up of pixels in a grid. These tiny dots of different colours make up the image. They are resolution dependent which means that resizing the image reduces quality of it. Rasters are easily converted to other raster formats. They are restricted to a rectangle and have a very minimal support for transparency.

Popular Raster formats:
• BMP
• GIF
• JPEG, JPG
• PNG
• TIFF
• PSD

Vector Image
Vector images are made up of individual and scalable objects which are defined by mathematical equations rather than pixels, so they always render at the highest quality. Objects may consist of lines, curves, and shapes with editable attributes such as colour and fill. They are scalable and will always look good no matter what size; a good example of a vector is fonts on a computer. They don’t have any background, it is transparent. They are inappropriate for photo-realistic images because it isn’t possible to make a photo into a lot of lines and colours.

Popular Vector formats:
• AI (Adobe Illustrator)
• PNG
• PSD
• TGA
• TIFF