if i understand you correctly, you want to temporary move your imagefiledata while you enter the MyMovies data which write its
own imagefile..and then put the original imagefile back.
i guess this should work
before you start the massimport of mymoviesdata, export your movies to an .mpl file
create a temporary library import the mpl file, and remove the data that
may overrun your data from mymovies, like artist, album etc..so when you (again) export your movies from the
temporary db, you will have a much smaller mpl file.
something like this
<Item>
<Field Name="Filename">D:\movie.avi</Field>
<Field Name="
Image file">BBC World C.jpg</Field>
<Field Name="Date Created">1246786043</Field>
<Field Name="Date Modified">1246802042</Field>
<Field Name="Date Imported">1247774457</Field>
</Item>
now run the mymovies data batch and after that import your mpl file into your main library, and your imagefile will be your original..
another way to do it if you dont like the temporary library idea, is to export to mpl and than search and replace your fields for example album to album
x so it will not overrun your data from mymovies
if you use sidecars files you better
disable it first. and this should only be done with files that
dont write tags to the actual file.
and please do some tests first and remember to backup
kingsparta had/has a plugin for this "replace master" that could copy and move restricted fields but i cant get it to work
ps.you dont have to create a temporary db for this, you can remove the tags in your main library and then export..the reason i suggest this is only caause i dont want you to mess things up with your original data