Ever wanted to change the default image capture of a mac to something else… like jpg… you can with this quick terminal command.
open a terminal window and type these two lines
defaults write com.apple.screencapture type whatever format you want killall SystemUIServer
replace whatever format you want with jpg, tiff, pdf, png, bmp, pict, etc…
Once you do that and enter the last command your next screen shots should be that format you choose. As an interesting side note, older versions of Mac OS X seem to have changed their out of box default image screen capture format over the years… for example.
Mac OSx 10.2 (jaguar) was .jpg
Mac OSx 10.3 (Panther) was .pdf
and Mac OSx 10.4 and later (tiger, lion, mountain lion) use .png
Happy Screen capturing