Try this:

For numbers, beginning in Cell A1 (no apparent need for ".jpg" in the second
column)

B1: =A1&".JPG"
copy down as far as needed

If you have a reason to use Col_A and Col_B (containing ".jpg"), then:
C1: =A1&B1

Does that help?
***********
Regards,
Ron

XL2002, WinXP


"Ms.Faye." wrote:

excel worksheet, numbers in first column, .jpg in second column; total of
2000 different numbers. How to combine column 1 with column 2 to be 111.jpg,
112.jpg, 113.jpg, etc.