Cannot change logos or advertising block image after first change

[Alaskan]

Hello,
I have been working on a PrestaShop install and have run into a serious problem; images will not change upon upload. For example, I will try to change the home page logo and browse to the file and select and then save and no change occurs on the front end. This happens with the home page logos and the advertising block image. With the advertising block image I browsed to an image and selected it and it changed it but then when I went to change it to something else it would not change again. I am not sure if this is a permissions problem (I followed the install directions to set permissions) or if it is not clearing some cache or temp file or what. I have searched and searched the forums and have not found anything that helps. I hope someone has the time to help me out. Thanks.
For now I have uninstalled or disabled a couple of the modules that I can't change the image with (home page editor and advertising block).
Thank you for any help you can provide.

[Alaskan]

Rechecked all permisisons and still having this issue. Really hoping to get some Dev response on this. I can't change the homepage logo or the image for the advertising block (and probably other images that I have yet to discover). I can edit/change the homepage text just fine. The problem is with the images. I go tot he homepage text editor, browse to a new image and save and it does nothing. The image in the editor does not change and the image on the front end does not change. I have spent hours searching for a solution and cannot find one. Really need some help on this one. Thanks.

[Alaskan]

UPDATE: OK, I may have discovered something about this... tried clearing Smarty / compile folder except index file and that didn't work. I am using MS IE 8 on this computer. On a whim I opened the site and backend on another computer using FireFox and I was actually able to change the homepage image and see it change on the homepage when I refreshed - all on the other computer and on Firefox. So, I refreshed the page on this computer in IE and no change occurred! This made me wonder about caching of the files with IE so I cleared the temp internet files AND changed the settings to check the site for changes upon each visit (instead of auto) and then tried changing the homepage image in IE and it worked! OMG. I tested it again and it worked. Haven't tested with the advertising block yet but am hoping that will work as it should too. So, this very frustrating issue may all be a cache issue... but, I am not completelty sure. And, if it is, shouldn't there be some IMS code within Prestashop's code to prevent IE (or any other browser) from doing that? Because I can see where the owner makes a change but visitors to the site don't see the change because of how their browsers cache the site?

Any other thoughts on this?