What is Adobe Photoshop?

                    Adobe Photoshop is a graphics editing program developed and published by Adobe Systems.
Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, 
Adobe Photoshop CS6 is the 13th major release of Adobe Photoshop. The CS rebranding also resulted in Adobe
offering numerous software packages containing multiple Adobe programs for a reduced price. Adobe Photoshop
is released in two editions: Adobe Photoshop, and Adobe Photoshop Extended, with the Extended having extra
3D image creation, motion graphics editing, and advanced image analysis features.Adobe Photoshop Extended
is included in all of Adobe's Creative Suite offerings except Design Standard, which includes the Adobe
Photoshop edition. However, in 2013, Adobe announced a new brand - Creative Cloud. And the Photoshop
version included in this suite is named Photoshop CC. The CC version has 3D content
as Photoshop Extended, which means the standard version is canceled.

                 Photoshop files have default file extension as .PSD, which stands for "Photoshop Document." 
A PSD file stores an image with support for most imaging options available in Photoshop. These include layers 
with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is 
in contrast to many other file formats (e.g. .JPG or .GIF) that restrict content to provide streamlined, predictable
functionality. A PSD file has a maximum height and width of 30,000 pixels, and a length limit of 3 Gigabytes. 

               Photoshop files sometimes have the file extension .PSB, which stands for "Photoshop Big" (also 
known as "large document format"). A PSB file extends the PSD file format, increasing the maximum height and
width to 300,000 pixels and the length limit to around 4 Exabytes. The dimension limit was apparently chosen 
arbitrarily by Adobe, not based on computer arithmetic constraints (it is not close to a power of two, as is
30,000) but for ease of software testing. PSD and PSB formats are documented. Because of Photoshop's popularity,
PSD files are widely used and supported to some extent by most competing software. The .PSD file format can be
exported to and from Adobe's other apps like Adobe Illustrator, Adobe Premiere Pro, and After Effects, to make 
professional standard DVDs and provide non-linear editing and special effects services, such as backgrounds, 
textures, and so on, for television, film, and the web.
              
               Photoshop's primary strength is as a pixel-based image editor, unlike vector-based image editors.
Photoshop also enables vector graphics editing through its Paths, Pen tools, Shape tools, Shape Layers, Type
tools, Import command, and Smart Object functions. These tools and commands are convenient to combine pixel-based
and vector-based images in one Photoshop document, because it may not be necessary to use more than one program.
To create very complex vector graphics with numerous shapes and colors, it may be easier to use software that was
created primarily for that purpose, such as Adobe Illustrator or CorelDRAW. Photoshop's non-destructive Smart
Objects can also import complex vector shapes.