The following function will rename all of the image files in a directory to be sequential. The parameters are the path of the directory that the files are in and the name of a function that will be used to sort the array of files through the PHP usort() function.
If you find that you are having trouble sorting data in a VARCHAR column in a MySQL database then you can try the following trick.
Lets say that you had the values 1,200,30,4000 and 5 and that you inserted them into the database in that order. When the following query is run on this data: