Say the data you're interested in changing is in cloumn D rows 1 - 1300
make a blank column next to your data (column E)
in the first cell of that column (E1) put the following formula:
=concatenate(d1,".jpg")
autofill down
copy column E
highlight column D
edit --> paste special...
then choose 'values'
now delete column E
That macro would actually work also, there is nothing special about it that seems to check that it's 6 digits long, or even a number. The only part that mentions the length of the string is the inputbox. It basically does (automatically) what I just explained. If you need to do this once, then do what I explained. If you need to do this on a regular basis, use the macro, but change the comment on the inputbox function to read whatever you want the user to see (change the part that reads "Enter the 6 number string to be appended to Column A" to read "<Whatever you want the user to see>" )