Screen Capture for OSX
Here are the various keyboard shortcuts that let you take various types of screenshots on an Apple Mac running OSX.
Apple Key + SHIFT + 3 + CTRL Screen to Clipboard
Apple Key + SHIFT + 4 + CTRL + Drag Selection to Clipboard
There is also a list of various keyboard shortcuts at ss64.com.
The screenshots are saved as pdf to the desktop, but can be easily changed by viewing them in Preview and then selecting export option from the file menu.
There are a large number of common image file formats which you can choose from and you can also give the image a more relevant name.
Image file formats include :-
BMP, JP2, JPEG, MacPaint, PDF, Photoshop, PICT, PNG, QuickTime Image, SGI, TGA, TIFF
By clicking on the options tab you can make adjustments to the bit depth and quality settings.