Graphic Tools

Resize Image

For instance, to change size of the picture to 22x22 pixels (Image Magick):

$ convert -resize 22x22 ⟨original-file.png⟩ ⟨new-file.png⟩

Convert to ICO

$ convert -background transparent input.png -define icon:auto-resize=32 output.ico

favicon - Converting GIF's, PNG's and JPG's to .ICO files using Imagemagick - Stack Overflow

Take Screenshot

To take a screenshot interactively choosing the rectangle area with the mouse:

$ scrot -s '⟨dir⟩/%y%m%d%H%M%S.png'

To check saved screenshot or to view other image (with Image Magick):

$ display ⟨image⟩