When I wanted to add pictures in the resources/drawable folder of an Android folder, I couldn't. When I right-clicked on the folder >> Add >> Add Files from Folder, all the png and jpg files couldn't be selected. Just to see if there was a problem with the images themselves, I copied the existing Icon.png, but I couldn't add the copy either.
I finally managed to add these files with the other option 'Add Existing Folder', but still wanted to know if I'm the only one with this problem, if it's a bug in the Xamarin Studio, or if I just missed something :)