Currently, when you use to Upload button in the web UI, there are very few automatic checks in place to make sure that you aren't accidentally uploading an erroneous file.
Request: improve the QA checks.
Current (problematic) behavior for images: You can “Browse” and import any file, overwriting the existing file in the repo (even if the file you browse to has a different GUID, version, language code etc. in the file name).
Current (problematic) behavior for topics: There are some validation checks for GUID, version, etc. when you upload an XML file. HOWEVER, if you try to upload an IMAGE file, no validations occur and the image file overwrites the XML file.