QS:Max filesize
From LimeSurvey Manual
許可された最大ファイルサイズ (max_filesize)
利用者がアップロードするファイルサイズの最大値です。
Example
If the maximum filesize is set to 1024 KB, any files larger than 1024 KB will be discarded, and the user will be asked to upload a smaller file.
Note: The final value shown to the survey participant is also depending on PHP settings, like post_max_size and upload_max_filesize. Of all three possible values (upload_max_filesize, post_max_size and max_filesize) the lowest one will be shown and used.