Or you could just use getMaximumFileUploadSize() from common_helper ;)

Yes, it's same :

Test if file size is biger : show the real error.
Don't test and show : maybe it's a problem with tmp, maybe it's a problem with file size ;).

2nd solution is really quickest ;)

We should show an information about the maximum file size beside the upload function and adjust the error message to account for both cases.

Btw, you can't test the file size if you cannot upload it ;)

Yes, then only one solution :
Return : "Unable to upload the file : validate if tmp/upload is writeabla or if filesize is less than ..."

Returned error is clear enough : http://php.net/manual/en/features.file-upload.errors.php

But surely better with http://www.yiiframework.com/doc/api/1.1/CUploadedFile and maybe a "settings" for ls3

Have to create a new extension for better reusing : then for LS3.

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=19333

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=19334

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=19341

Version 2.50 Release 160606 released