Renamed image files show up wrong online

This is continuation of an earlier posting: I need to change the name of certain image files prior to launching the website online. Merely changing the name of the file doesn't do it as the file simply reverts back to its original name on being dragged into iWeb . It was suggested that I open the file in an application such as photoshop, then do a save-as with a different name & once again drag it into iWeb. That seemed to work, but when the site was published the file showed up online with its original, not the revised, name! This was confirmed by checking the html code in an online editor. Yes, it is possible to change it in the editor; however, this is a cumbersome process which has the added drawback that any changes are wiped out if the site is republished.

So somehow IWeb seems to be writing the wrong code or referring to a file that no longer exists. Any idea of how this can be corrected?