Thank you both for the GIMP tip.  I tried GIMP many years ago and at that time it required a hard drive, root directory installation which would not have helped my situation but on your suggestion I just had another look at it.  After a bit of a search I found a portable version of GIMP that goes through an installation process but installs onto a flash drive.  Just finished trying it out and it worked on the company computer without a hitch, so thanks again for your help.

If anyone else is interested this is where my search led me.  

http://portableapps.com/suite

This site has portable versions of free, open source programs under the General Public License.

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