Some glazing is normal. It is hard to tell from that picture due to the reflection.
I just installed a Dayco 5040465 today and had no problems at all.
From past experience, it is not uncommon for aftermarket belts to stretch a bit more than the OE belts. Therefore, it may be necessary to tighten them a
hair tighter than required. The revised spec for the 2007 Yaris is 10-11mm (used belt), not the 11-14 that the manually originally specifies. Since you are using an aftermarket belt, I would tighten it a bit tighter...probably 7-10mm.
This is how I tightened it: use a prybar and pry HARD between the engine mount and the
reinforced area on the alternator. If you look in this post, the "reinforced area" that I am referring to is the rounded area that sort of sticks out:
http://www.yarisworld.com/forums/sho...85&postcount=1
If you use a very long prybar (24") and pry hard against the areas I mentioned, while still holding your prybar, fully tighten the 12mm bolt at the top of the alternator. This should fully secure the alternator in the position that you desire. Then f/u by tightening down 14mm bolt at the bottom.
If you do this with a new belt, the belt should have very little deflection. After the 10-15 min run time, you should feel a small amount of deflection (7-10mm) which is just a hair tighter than what Toyota suggests...and your noise should go away.