I never had that problem with the old app, but now they always pop up when Album generates them. Even if I delete them, half an hour later they are back.
The folders the thumbnails and cache pictures are comming from are /sdcard/Android/data/com.sonyericsson.album , com.sonyericsson.music and com.sonyericsson.movie.
What I tried was to make a new .nomedia file in all of these folders, but if I do so the folders are still in the Album app. When I click on them they are just empty, but the app shows "22 pictures" beneath the title of the folder.
I like the new Album app more then the old one.. Is there any way to get rid of these folders without using the old version? :/
edit: Also these goddamn facebook images or smileys or whatever they call them are now showing, never had that before too.