You're talking about my tutorial, Creating a Photo Vignette: . And your first problem involves looking at your Layers Palette. After you've added a Mask , you'll see two icons on the palette for your layer. The one on the left shows a small representation of the image contained on that layer. The other, to the right, shows what the mask looks like. You have to click which one you want to work on. Whichever one is active will have a small black outline around its icon to show this. Click on the layer mask icon, then you can paint, or blur or apply other filters or whatever and it will only affect the mask. Click back on the image icon to work on the image.
Your other problem involves not having white set as your background color. To restore Black & White as yourForeground and Background Colors , hit the D key.
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