The same thing happened to me. This issue should be resolved, simply by using another browser. Internet Explorer can't upload the image, and you've probably used another browser at the time you uploaded the first image. Just try another browser. I used Firefox last time, and it worked.
You can thank the administrator, slize106, if it works like it should.
You can blame Internet Explorer's lack of binary-to-text file mode support for this.
Internet Explorer really conforms best with Microsoft's otherwise horrible methods of handling data over an internet connection. It doesn't conform to the true standards because those weren't set by Microsoft. :P
That's why I prefer Firefox, personally.
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