The email server didn’t recognize your username/password combination using gmail to share

Up until last week I have been able to share photos in iphoto11 using my gmail account. Now, I get an error message saying that the email server didn't recognize my username and pw combination. I have tried deleting and re-entering the info needed to add the gmail account under iphoto preferences, but it only can send through my icloud account. Is this the only way?

I am using iphoto11 v9.4.2 on my mac OS X 10.8.2.