Export pictures from Kphotoalbum version 4.1.1 to kim file (either chosing option 1 - copy the pictures into the kim file or option 3 - automatically copy pictures next to kim file).

Importing kim into Kphotoalbum version 4.5.
Chose picture path to be subfolder of root of kphotoalbum collection (home/me/root-of-kphotoalbum-collection/2014/new_pictures)
Import done
Checking thumbnails - showing standard thumbnail, because path of the pictures is expected to be in the root instead of the appropriate subfolder.

Reproducible: Always

Steps to Reproduce:
1. Export picture of kphotoalbum 4.1.1 into kim
2. Import kim into kphotoalbum 4.5
3. Chose subfolder of root of kphotoalbum pictures
4. Check if path of picture is right (subfolder)
5. Nope

Actual Results:  
A standard thumbnail is shown, because the path of the picture is wrong

Expected Results:  
Displaying the right thumbnail

I know, that the creation of thumbnails is handled differently in version 4.5 than 4.1.1
But this is not the problem.

Workaround:
Open index.xml in an editor (gedit).
Search for file="DSC and replace those strings with file="2014/new_pictures/DSC