Not always is the Flashuploader of WordPress a blessing and several times I preferred to have it switched off. Usually if the blog is not online and is offline behind a proxy and firewall.
With the help of the Browser uploaders there is less trouble and therefore easy to abandon the added value of Flash uploaders, like loading multiple files simultaneously. You can disable the Flash uploader by using a filter. This can be done either in your theme, stored in the
functions.php or in a Plugin. I use the option of switching off with the help of the Plugin Adminimize. Alternatively, the following syntax helps and the browser uploader will be available only.