When you try to upload more than 1 file, but less than 10 (i.e. using regular UPLOAD FILE, and not BATCH ADD), the drop down list
for album selection does not remember your selection between files and you have to choose the same album multiple times - for each
file.
In order to fix this, open up "upload.php" in your favourite text editor, go to line 176 and change $_GET to $_REQUEST
That is all.
Thanks for your report. However, this doesn't look like a proper method to avoid sanitization.