Free extensions for Joomla!

Hi!
I was using an olter version of Joomla 1.0 and I've decided to move to 1.5.
So, I've created a new installation of Joomla in a subdirectory \mysiteJoomla15 and I've started installing all components included zoom. Eventually, I completed the transition and copied the Joomla1.5 directory into my root directory.I've also updated the ZOOm configuration redirecting zoom to the new directory. Everything worked fin included Zoom. I could also add several photos.

I don't know what happened a couple of days ago but after adding several photos and cancelling some of them from the administrator menu, the new photos are shown correctly in the backhand (administrator) and they are not shown in the front end where a warning about the imagesize is shown. It tries to search the file into the old \mysiteJoomla15 directory.

Is there anyone who could try to help me? Is there any configuration file I have to manually change? Where is located this information?