When uploading you on some site (including monmonja.com) dont have a clue if your upload is progressing or not. With firebug (extension of firefox) you can monitor your upload progress.

First you need to have Firefox
Then install Firebug

To monitor your upload:
1. Open firebug by going to tools -> Firebug -> Open Firebug
2. Enable Firebug if necessary
3. There are many tabs in Firebug, Click on the Net tab (the last tab)
4. Scroll down if there are too many requests
5. Go to the site where you want to upload something
6. Try to upload a big file
7. Finally you can see that the kilobytes of what your uploading is increasing as time goes by,
if the KB stop then probably there is some error and you need to re upload it.