I fixed it for myself by renaming some image files, swapped the .PNG files into .png and the logo file into logo.png. The reason why no one has complained before is probably because people used windows or they fixed it or they just played it without most images like the map images.
The reason why it breaks on non windows systems is that browser one uses tries to open file called logo.png on the img/logo/ subfolder but there is only Logo.PNG there. Windows just ignores upper and lowercase and the browser finds the file. But on non windows system query for file called logo.png fails for that can be entirely different file.
On Linux etc you can have files like Logo.PNG, loGo.PnG and logo.png on same folder but windows just says that file with the name already exists.
Sorry for the long rant :P