Originally Posted by fusionx

Grab a file converter that has Windows Explorer integration. Do a search across those directories (with Win. Explorer), then select all the results, right click, do the conversion removing the original. Search retrieves all the files with full paths, making it easy.

Delete the old files from the web, upload the new.

Done.

Picaview does this.. not sure if it's still supported or not. http://files.brothersoft.com/picaview.exe