I know that I'm not the first and I definitely won't be the last blogger to offer tutorials and tips etc for blogging and HTML/CSS but I really want to try and offer something other than the generic advice that is passed around. I'm not saying that what I am going to offer is going to be brand-spanking new but hopefully it will help you out nevertheless. Without further a do, this is one of the ways in which you can quickly brighten your images in photoshop (I'm using the CS5 version but this should work in any version of PS).
001: Open your image that you are going to use. Duplicate the layer (by pressing CTRL+J) or by right-clicking the background layer and selecting duplicate layer.
002: Still in the layers section, click where it says Normal and a menu should pop up; click on Screen.
003: You should notice how much brighter your image is already, if it looks okay, that's you pretty much done. However, depending on the image you have chosen, this could have made your image a little too bright so to combat this, lower your opacity until you get your desired look.
004: To finish off, merge your two layers together (CTRL+E) or right-clicking and selecting merge visible.
And it is as simple as that. If you have any questions or requests, feel free to ask them in the comments below.