Remove/reset/auto empty 'alt' attribute

Hey you guys,
I have a galleries with lots of photo’s in it. Displayed using the NextGEN gallery plugin.

Is there a way when uploading photo’s(/media) to have the ‘alt’ attribute automatically not filled in, instead of having the file name automatically as ‘alt’? So I can write my own ‘alt’ or else have nothing as alt.

Using a filter or whatever is possible.
Or it want it disabled for the page template of the albums or just empty (on the template or the whole site).

I hope someone can help me out on this one!
Thanks in advance!