Welcome. This is where all other (Non Wikipedia Capable) Images are stored. Use the file name in your own wiki/sps to import image from this site.
Upload an image while editing a category to put an image in that category. Make the name of the image is changed to something sensible before uploading because otherwise, it will have to be manually transferred. Images uploaded elsewhere will require categorisation later on.
If you just want to upload image the traditional way, try the Simple Uploader Here
Here's a list of Recently added files to the commons. Also, check out the Category:St. Paul's School, Darjeeling at Wikimedia Commons.