Difference between a bitmap and a vector graphic:


A bitmap is a graphic that is made up of pixels. Thay look like small squares when you zoom in, they are used widely in packages such as microsoft word. Bitmaps can only be resized to a certain level becauase you loose quality.bitmap files are more suitable for photo-realistic images that require complex color variations. They are not easily scalable because each bitmap-based image is mapped to a non-flexible grid. If a bitmap-based image were to be enlarged, it would lose its sharpness. All edges within the image would appear to be jagged.

File names for bitmap-based images usually consist of extensions such as *.PSD, *.JPG, *GIF, *.TIF, or *.BMP.

In general, bitmap-based files require more computer memory for file storage than vector-based files. The former contains all information for every single pixel of the image while the latter contains only the defining mathematical formulas for each element within the image they  do not rely on mathematical formulas to define their various elements. Each bitmap-based image is mapped into a grid. The size of the grid is based on the image’s resolution. For example, a bitmap-based image of 1 inch x 1 inch with a 600 dpi(dots per inch)resolution would be defined by a grid of 600 x 600 pixels. A bitmap-based image is like a mosaic of pixels with each pixel holding a specific color value.


Key Points About Bitmap Images:
• pixels in a grid
• resolution dependent
• resizing reduces quality
• easily converted
• restricted to rectangle
• minimal support for transparency



A Bitmap Image–shown zoomed in with the original size in the upper right corner. Notice the individual pixels that make up the image.


vector images generally contain well-defined elements such as curves and shapes of various colors. These elements can either be pure graphics, western alphabets or Asian characters. Each element is defined mathematically by the computer. EG, if a vector-based image contains a red dot, then information such as the location of the circle’s center point, the length of its radius, and the color, red, would be the essential information for this image file.

File names for vector-based images usually consist of extensions such as *.EPS, *.AI, *CDR, or *.DWG.

files are more suitable for illustrations that require precise measurements. They are also easily scalable due to their mathematical nature. However, the vector-based file format has its drawbacks as well. It is not good for displaying photo-realistic images such as a photograph because images of this type generally do not contain well-defined shapes and curves.


Key Points About Vector Images
• scalable
• resolution independent
• no background
• cartoon-like
• inappropriate for photo-realistic images
• metafiles contain both raster and vector data


Vector and Bitmap Differences–vector images are not confined to a rectangular shape.


Graphic formats:

 GIF: is a commonly used image format for Internet graphics. It limits the number of colors used in an image to a maximum of 256, thus reducing its color depth. As an image being converted to the *.GIF format, all the colours within the image would be forced to best match the 256 index colours pre-determined by your computer’s operating system. This format is most suitable for images with few solid colours such as icons but are less suitable for photo-realistic images due to its limitation in colors.

JPEG:  another commonly used image format for Internet graphics and for sending pictures as attachments via e-mail. This file format is suitable for displaying photo-realistic images because it does not limit the number of colors used any given image.

TIF:  bitmap-based file format, is commonly used in image editing software. Picture Publisher and iPhoto, the two image editing software that come with Mustek scanners, use this file format as their default file format for saving scanned images. This format generally does not compress the size of the image file significantly unless the image is scanned in Line Art Mode.


 PNG.  “Portable Network Graphic.” This  patent free format was designed as an alternative to the GIF format which has many copyright issues . Like GIFs, PNG files are lossless,they don’t lose any detail when they are compressed. They support up to 48-bit color or 16-bit grayscale and typically compress about 5% to 25% better than GIF files, they do not support animations like GIFs do. A format similar to PNG, called MNG, is currently under development, and will support animations.

PSD Layered file format. The layers enable an illustration to be built with individual graphic elements that can be moved over and over to obtain a desired result. When the PSD format is converted into a TIFF, JPEG, GIF or other graphics format, the layering is “flattened” into one bitmapped image.EG it would be very difficult to build a collage of many images overlapping each other without layers, because the placement of each object would have to be perfect from the start. Without layers, once a small bitmap is placed on top of the large bitmap, it becomes “one with the image” and cannot be altered at all or at least without major effort.