You’re right, but nothing has changed, 'cause the problem is another. And this is a big problem regarding any image you try to upload with any smartphone and yii validation rule philosophy.
If you try to load an image file of your pc, you point to the real file, so the validation rule works fine. But if you try to load an image file from your smartphone, you don’t point to the real file to upload to, but to the thumbnail related. So the validation, obviously, fails.
And this is a really big problem, but for this and other cases the apps for smartphones exists.