CSS, or cascading stylesheets, allow you to define how web page elements are displayed.
Specific margins or colors can be associated with elements on the web page; Headers and links, for example. When style sheets are applied to a new page, the elements are changed according to the specifications of the style.
To fill an image means to paint the inside of it with a selected color or pattern.
The fill can be used to create shading and other simple effects. In HTML, a popular technique is to fill tables with colors, especially in long lists of information. For example, if you are making a web page showing the 50 top-grossing movies of the year, it will be easier to read if you fill the rows of the table and alternate the background colors.
Flatten is a function in image-processing programs, such as Adobe Photoshop, to combine multiple layers into one file.
For example, in order to move the file to another program or save it as a GIF or JPEG, you will have to use the flatten function to combine all layers into one.
Blur filters locate significant color transitions in an image, then create intermediary colors to soften the edges. The Gaussian blur is one kind of blur filter that uses a mathematical formula to create the effect of looking through an out-of-focus lens. Gaussian is a mathematical term named after German astronomer and mathematician Karl Friedrich Gauss.
A grayscale image uses only shades of gray to represent an image.
Black-and-white photographs can use a virtually unlimited number of shades of gray, but most computers can display only 16 or 256. To grayscale is to convert a continuous-tone image, like a black-and-white photograph, to an image made up of pixels. Grayscaling is different from dithering, which uses either black or white pixels next to one another to simulate shades of gray. In grayscaling, each individual pixel can be a different shade of gray.