Archive Explorer - Desktop app coding

I have a question, which says: I have a graphic template with .jpg files inside, there is a way of changing a .jpg that would be a logo but that request opening a graphic software and changing it there, but I would like to facilitate this task for my clients. This app would have to open / explore an archiver (a single file), the client will drag out the jpg / png file - LOGO - modify it in Photoshop and drag it back inside archiver replacing the old file That's all. This app should be available for Win and Mac. I will sell it for to my customers to facilitate their work. I will supply a testing file after making an agreement. / Optional It would be great if it would be possible generating custom Serial Number for every customer based on their Name Middle name as Surname /