Image and Graphic Files

Common Problems

Susie Benaim, Zara Babakordi, Eyoel Fanuel,

Philippa Wright

What is the difference between a vector based image and a bitmap (or

raster) based image?

• Bitmap is made of pixels in a grid and are resolution dependent so the quality can be changed if the size is decreased or increased.

• Vector based images are made up of scaleable objects defined by mathematical equations rather than pixels, so always have high quality. They are resolution independent.

Sharper images

Blurry images

What is the difference between a GIF formatted file and a JPEG?

• JPEG format is used when an image has many colours, whereas GIF is more suitable for images with fewer colours.

• Knowing the difference between these two formats can help you select the best option when saving your images.

• Eg. Saving a photo for use on a website will be of better quality when saved in JPEG than GIF

What is the difference between and embedded graphic (image) and a linked

graphic (image) in a Word or Powerpoint document?

• Embedded graphics (the default image) are used when working on an imported file independently, whereas link graphic images remain independent of the illustrator file.

• With embedded images the file size does not matter, whereas with linked images, the size can be altered.

Embedded images are important as the file size does not matter and can be constantly moved between different files

What is a 'colour palette'?

• A colour palette is a set of colours defined for use within an image.

Small palette files Eg. GIF files store a 4 or 8 bit index for each pixel.

Image is a lot smaller than that of 24 bits.

Large palette files

Eg. TIF and JPG files store a 24 bit index for each of the millions of image pixels.

What is lossless compression?

What does the FBS skills wiki say about using PNG files?

What is BAD about using .bmp format files in your work?

What is Flickr?

References

• https://wiki.leeds.ac.uk/index.php/FBS_Faculty_Skills_Guide_-_Computers

• http://en.wikipedia.org• http://www.uic.edu/cuppa/udv/ai/basic.htm#link• www.fijdesign.com/glossary.htm• www.scantips.com/palettes.html