Wierd bug - items have different thumbnails and fullsize images

After I updated Omeka from 2.2 to 2.5 i discovered a lot of items in a particular collection have the correct thumbnail image but wrong image in the item page (it shows the image of next item). I deleted the collection and import again with csv import. But Problem is still there.

what should i do? Delete Omeka and install everything again?


i discovered that the Problem occurs when items have the same Titel. Does omeka matches the images with the Items by titel? how can i change it to identifier?


the problem was Clean URL Plugin using title to create the URL. I changed it to identifier, everything is fine now