You could just press the print screen button on a PC or use the screen capture tool on the Mac and crop that in Microsoft Paint or Photoshop or whatever.
Do you have Adobe Acrobat DC? If so, consider:
You could edit in Photoshop, then save it as jpg from there.
Alternately, if you don't have Acrobat (and are using the free Adobe Reader) consider using a screen snapshot tool such as Snagit or the built-in Windows Snipping tool or Mac screen capture shortcuts.
sorry - not enough detail - using Acrobat Pro of iMAC - don't have photoshop - I know how to use edit tools to either choose an object or crop - I can't seem to get what I copy to paste into a work doc or anywhere else.......
[Asking in the correct forum helps... Moved from non-technical Forum Lounge to an Acrobat forum... Mod]