in DAM Update Asset workflow, there's a step Process thumbnail. In that if i manually add renditions, those gets generated. Then why do we need to make use of image magick and ghost script? I want to understand the usage, any heads up will be helpful!
These Image Processing and Management tools like (ImageMagick etc) do not only generate custom renditions but can be used to create, edit, compose, or convert bitmap images. It can read and write images in a variety of formats (over 200) including PNG, JPEG, JPEG-2000, GIF, TIFF, DPX, EXR, WebP, Postscript, PDF, and SVG. Use ImageMagick to resize, flip, mirror, rotate, distort, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and curves. More details are available in http://www.imagemagick.org/script/index.php .You can use ImageMagick features from the Adobe Experience Manager (AEM) command-line based media handler to process images.
On the other hand,Ghostscriptis detailed as "Interpreter for the PostScript language and for PDF". It is a suite of software based on an interpreter for Adobe Systems' PostScript and PDF page description languages. Its main purposes are the rasterization or rendering of such page description language files.