I received an attachment that was scanned as a picture and tried to change it to a word document so that I could print it as such. Now, whatever change I made causes jpg's to open in Word, encoded so that I can't read them. I think I changed a property setting when the scanned picture was open.

Try saving the attachment to hard drive if haven't already and then rename back to .jpg

Don't know how you tried to change to word but you may have made Word the default app to open JPG files

Save file to hard drive
-right click on the jpg file
-choose Open with..
-select Choose default program
-highlight your image viewer
-put check in box at bottom to Always use selected program