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1. Image file
format
PNG, JPEG,
GIF, SVG &
EPS
GROUP 4
Q03/Q04

2. What is image file
format
Image files are a way of storing digital
image data on a smart device and the
smart device know it is an image file either
by its extension Like PNG, JPEG or by its
magic number which is a few bytes at the
beginning of the file that help identify it.

3. Raster & vector
graphics
1.Raster(pixel) graphic
.made out of pixels.
.each pixel hold a color value.
.includes PNG, JEPG, etc.…
2.Vector graphic
.made out using shapes from math
formulas
.each shape is made of
Coordinates, Strokes, Curves.
.Includes SVG, PDF, etc.…
A raster image next to a vector one

4. The two main compression techniques
Lossless
Compresses data without losing any
info by storing repeating patterns such
as a collum of pixels of the same color
as a description of the pattern as such
the data is not lost and can be
restored by replacing the pattern with
the original sequences resulting in
bigger files
lossy
Compresses by losing some info as it
works on rounding high frequency
details as the eye can't notice these
changes but because it rounded
these values when we try to restore
the original data the restoration is
approximation resulting in smaller file
sizes

5. Understanding some raster file formats
PNG
A lossless compression
format that support alpha
transparency and it handle
text and lines better than
any other raster-based
image best uses are in logos
with transparency and
screenshots
JPEG
A lossy compression format
that support up to 16.7
million colors and it is the
default format for most
digital cameras and
smartphones best uses are in
photographs and printing
GIF
A lossless compression
format that support
animation with limited colors
each GIF contain multiple
images that are displayed in
sequence best uses are in
loading icons and online
memes

6. Format
Signal
Representation
Transform /
Compression
Quantization
Color
Depth
Transparency
Structural
Use
JPG
Raster, 24-bit
RGB
DCT +
Quantization +
Huffman
Lossy,
discards
high-
frequency
data
16M+ None
Continuous-
tone images,
photos
PNG
Raster, 24-bit
RGB + 8-bit
αlpha
Deflate (LZ77 +
Huffman) with
line filters
None
(lossless)
16M+ Full α (0–255)
Graphics,
logos, sharp
edges
GIF
Raster, 8-bit
indexed
palette
LZW
(dictionary)
Implicit (256-
color limit)
256
only
Binary (1-bit)
Animations,
simple
graphics

7. A brief history of
PNG
PNG started development in the year 1995
by Usenet group and was finalized by the
year 1996 and an extension of PNG called
APNG was created in the year 2004 which
allowed for animation support.

8. A brief history of
JPEG
JPEG started development in the year 1986
by JPEG committe and was finalized by the
year 1992 and while they worked on a new
version called JPEG 2000 right after finishing
the original and that provided higher image
quality due to using lossless compression but
the lack of interest due to lack of support
made it an unpopular choice that most
browsers avoid in its inception

9. A brief history of
GIF
The first version of GIF was called GIF87
created in the year 1987 by CompuServe
but unlike the version we use now that is
called GIF89 the older model lacked the
animation support.

10. Understanding some vector file formats
SVG EPS
A lossless compression
format that support scaling
to any size without losing
sharpness best use for logos
and text as it is not realistic
An uncompressed file format that
store vectors as a postscript code it
also support a preview image that is
low resolution to show thumbnail
without rendering the code best
uses are for old application that
require postscript files

11. A brief history of
SVG
The first version of SVG released in 1999 by W3C and was
made to provide vector graphics without the need for
plugins and while a new version called SVG 2 started
development in 2011 it is yet to be released

12. Thank you