Three recent uploads have failed to complete, leaving the bottom of the images grey. This triggers Sandbot to tell me it's an incomplete image, which is something I already know. After failing the upload it then waits for about 7 minutes then gives the "Unknown Server Error". I have now lost the lengthy description text I entered for the image because steps cannot be retraced. Fustrating in the least and I suggest someone takes this problem by the horns and actually makes Upload Wizard usable.
Marking as low priority mostly due to the small amount of time available to work on UW, but also because this seems to be a poorly-defined issue that may take a significant amount of time to properly diagnose. If we get more information about the file that failed, any errors/warnings in the console, etc. maybe we can revisit this. Though also if this is an isolated incident, it hardly seems "(un)usable" at least in the majority of cases, so without further reports, the priority may stay where it is.