Shrink the size of a photo

Open an image in Photoshop. Select Image Size from the Image menu.

The dialog box that appears shows the current size of the file in the top left section of the window. As a rule of thumb, it's a good idea to get pictures to below 100K before mailing them. This picture is 17.2M, which is too large to mail. Google has a file size limit of 20M for attachments, so this would make it through Google, but not necessarily all servers on the path to the recipient.

Unless you want to make the image "fatter" or "skinnier," make sure the constrain proportions option is checked before changing sizes.  With this setting, you only need to change width or height, and the other value is automatically calculated.

If this image is changed to 500 pixels wide and kept at the 230 pixels per inch resolution, the file size will be 550.4K.

Photos that are going to be printed should be at 300 dpi or better. Photos that are only going to be displayed on monitors only need to be 72 dots per inch. This image can be further reduced by changing the resolution to 72 dpi.