Rename files in two different folders

[ThiefOfTime]

If the files in your second folder are defining the names, then you can read the files of this folder (see: https://stackoverflow.com/questions/3207...-directory)
since the last digits of the files in both folders match you can use the split function on the .jpeg file names
for example

some_file_2dir = '07_2506.jpeg'
new_name = '%s.xml'%some_file_2dir.split('_')[1].split('.')[0]

and since you can call system functions like the move command mv you can then move the files of the first folder to the same location but with the new_name. Remember to check the names of the files in the first directory :)