Emailer v3.0 (May, 2018)
This is a little Windows program that emails pictures. There's no need to configure anything, no need to sign up for an account, no ads and no fees, it should just work right out of the proverbial box. And it'll automatically split large numbers of pictures into multiple emails, so you can easily send large albums in one shot. Because we're handy like that.
Note that to keep things simple there's no installer, just download and run it.
Usage is pretty straight-forward: type in the addresses you want to email pictures to (separate multiple emails with a comma) and drag your pictures onto the large message field.
If you want to get fancy you can click Preferences -> Edit Config File to enable sending full sized pictures, or using your own mail server, and a few other things, but the standard settings should be fine for most people.
Note that this is thriftshop ware! That means that if find it useful you're karmically bound to send me something interesting from a thriftshop.
Updates:
v3.0 (5/29/2018): Added the ability to split large emails into multiple small emails and gave it a bunch of under-the-hood love
v2.0 (9/16/2009): changed the SMTP port to 587 so it should work even with ISPs that like to block ports. If you have no idea what I just said, don't worry about it.