1. Start simple:
The first time you click the add photos button? and select a gallery, you'll see this:

If you don't see it, no worries. We took you straight to the uploader you used last time. At the bottom of the page you'll see a link to choose another uploader. Click it to see the choice for the Simple uploader.
Now choose the Simple uploader. You'll be asked to click trust. Here's a picture of what the trust button looks like:

We hate telling you this, but if you didn't click trust when asked, you have to quit your web browser and re-start it.
2. Select photos:
Click add files and locate your photos on your computer.
Click on the first image you'd like to add.
Hold down the shift key on your keyboard, and click on another image. All images in between will be selected as well.
Click open.
3. Send them on their way:
Add as many photos as you'd like. Then, just click Upload!
A progress window will open so you can watch your photos as they are added.