If you're in need of a bit of image editing, there are some fantastic web applications available for just that purpose
- Pixlr
- Phoenix (by Aviary)
CSS3/Webkit filters is the way to go for adding effects to your images. Keep in mind that currently these features only function with Chrome Canary and Webkit Nightly browsers. Effects that can be applied include grayscale, blur, sepia, saturate, opacity, brightness, contrast, hue-rotate, and invert.
Resources:
CSS3 Filters
Alternatively, setting the opacity
might suffice.
img {
opacity: .7;
//the line above works perfectly in Firefox, Safari, Chrome, and Opera
filter: progid:DXImageTransform.Microsoft.Alpha(opacity=70);
// the line above functions in IE6, IE7, and IE8
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(opacity=70)";
// the line above is exclusively for IE8
}