Create application that compresses files

Need a utility that can read large folders of files and create rar files for each folder and sub folder separately. Detailed Description: I have a directory of 100 folders [foldername1], [foldername2], etc. Each of the 100 folders have 10,000 png files and one subfolder called [small] with 10,000 smaller (low res) versions of the same file. I need a utility that will compress all the png files "inside" of each of the 100 folders using name of the folder i.e. [foldername1].rar.. then script will recurse sub folder and create a "new" archive inside and name that archive [[login to view URL]]. Once its done creating an archive inside foldername1 and an archive inside "small" folder.. it will start the next folder - folder2 and repeat Once its done with all folders, I will have 2 rar archives in each of the 100 folders or 200 rar archives totals.