I'm Dragan Simic from the English Wikipedia, where my account has the same username and functions as the home wiki for my unified login. Please have a look at my Wikipedia user page for further information.
So far, on Wikimedia Commons I've uploaded a bunch of images, partially by transferring over here the images I've already uploaded to English Wikipedia. At the same time, I've created a few dozens of new categories and used them for finer-grained classification of various computer-related images. Here's the list of my contributions to Wikimedia Commons, the list of uploaded images, the list of created categories, and some edit stats.