Contest. Hiden text

The positive reaction to my last contest encouraged to make more of them. And not only me.

This time I was approached by another Leo member @rival, from Netherlands, who made a graphic puzzle with a hidden text.

He sent to me a rather simple graphic png file, and asked me to find a secret. After some time of torture on my brain, I gave up, and asked for a hint.
After the hint - all went easy.

We both then agreed that his hint was probably to straightforward and easy, so we modified it a bit, in case we need it.

Without not much more else to say at this time, here is the file:

All you have to do is find a secret six word text.

Winer will pick my prize, which will be 2 LEO during the first 36 hours
Prize will DOUBLE every 36 hours until this post expires.

Good Luck !

@rival & @onealfa