This may not be in time to assist you in this instance Glen but it may be of help for others or for future use. My apologies if it is verbose.PDF
When a PDF has been closed so that you are unable to select from the document, I have found that when I "Save a Copy" with a different name I am able to then select from the copy.SCREEN SHOTS
If you "have" to work with screen captures it is worth increasing the zoom size to highest possible/acceptable resolution. The PDF reader will (should) have a zoom selection on the menu and explorer has one in the bottom right hand corner.
To capture the screen, the print screen (Prt Sc) usually to the right of the function (F#) buttons can be used to place an image on the clipboard. Different machines (systems) work in different ways and some experimentation may be required as to which buttons do what on a given computer. On the machine I am currently working on hitting the Prt Sc button will paste a copy of the entire screen to the clipboard, whereas Alt+Prt Sc will paste a copy of just the application as shown on the screen (even if the window only takes up say half the screen) to the clipboard.Placing the screenshot in an application such as Word, Notepad or what ever will embed the picture in the document/file without showing the image file extention (eg .jpg) that Photobucket seeks. Thus, it is best to paste (Ctrl+V) the screenshot directly into your photo editor application and (edit then) save the image ready for upload/use.
Picasa allows for direct screen capture ready for editing. Editing will most likely be required as a screenshot will take the full screen or full screen shown for the application one is using; not just the image you wish to capture. WINDOWS PAINT
Should you being working on a machine that either doesn't have your preferred editor or access to the web to allow download of an editor (eg Picasa) or access to an editor (eg Photobucket) all is not lost (you may be working from a disk/file someone has supplied). Since Windows 98; Windows Paint has been supplied with the Windows operating system. While not as slick as Adobe, Photoshop etc it does the trick. (Start>>>All Programs>>>Accessories>>>Paint)
Ctrl+V the picture onto the palette click on the crop icon, outline the area of the picture you wish to retain, select from the menu Image>>>Crop and you have the item you wish. When saving the image you can select the format best suited to your purposes.
One thing to look out for though is that when one crops a picture in Paint, if one uses the Edit menu Cut item rather than the portion required being retained on screen it is taken to the clipboard and requires pasting to a new palette which one then saves. When selecting the new palette a dialogue box will ask if you wish to save changes to untitled ... just hit the don't save button.APPLICATIONS/TOOLS
There are a number of applications available to "garb" just a portion of a screen and save it as a picture (jpg, bmp etc). Some freeies are:
If you have Vista OS, you have a tool called Snipping Tool
(Start>>>All Programs>>>Accessories>>>Snipping Tool) very easy to use, though formats to save are limited. If you wish to further edit (crop the picture, rotate etc) it is available to immediately use in your preferred editor.
If you have XP you can download the Snipping Tool for XP from http://www.blazingtools.com/downloads.html
it is currently the very bottom selection on the page gained from this link.
If you really need all the bells and whistles a fully functional version of SnagIt is available as a 30 day free trial from http://www.techsmith.com/screen-capture.asp
This is compatible with Windows 2000, XP and Vista; though one should check the system requirements before downloading.
While i haven't used these sites , McAfee site adviser gives them a green code.
I hope this is of some use.