Saving an Image for the Web
Photoshop CS6 Tutorial
How to Save an Image for the Web in Photoshop
To effectively save your image for the web, it must be converted to a JPG and compressed to decrease the file size.
Open an image in Photoshop (File > Open).
Duplicate your original image by choosing Image > Duplicate. Close your original image.
Adjust the image size by selecting Image > Image Size. Set the Resolution to 72 ppi and enter values for Height and Width. These values are usually less than 1200.
Choose File > Save for Web.
Set the Format to JPG. Try the various Compression settings (High, Med, Low, etc) and note the file size and image quality.
You could also select one of the JPG Presets to set the compression.
Click Save to name and save your file.