How to create a variable that auto increments within a loop

 have a requirement to extract product images from a web site and need to maintain the image sequence in order to display correctly on the new site. Is there a way to create a variable that increments for each URL extracted?

eg:/

ImgURL                                                   ImgSeq                                  
http://somestring.sdkhl3sd.jpg                1
http://somestring.sdhkwal.jpg                 2
http://somestring.qsdkwe.jpg                  3
etc