There are several photo sites and networks today that offer sharing and more. The features these sites like Flickr, Photobucket, ImageShack, Picasa, SmugMug, Slide and others. Most of these sites have the ability to do more than share via email. By using tags and keywords these sites allow you include your photos with larger collections based on the metadata. This can help you get clicks to your photo stream if you add your photos to a larger group. Visitors can find your site/blog from there and also search results of your properly tagged images.
Some of these sites do have restrictions on how many photos in terms of memory size you can upload and share in a given time period. Of course you have the ability to upgrade your account if your volume exceeds the limit. For example, Flickr allows a monthly upload limit of 100MB.
These sites also allow you to embed images into blog posts, web pages and other digital media. Some like Slide will put a watermark on the image so be sure to test how the images appear to get the right site. Picasa works well with other Google tools since it is part of the Google family but also has upload bandwidth restrictions. Again there are many pros and cons for each site so review their features and benefits to find the right fit for you.
By adding photos to your site or blog you are likely to get more visitors from the simple fact that humans love to see other people, places and things. From a communication standpoint, a photo is invaluable since it gives the reader another view of the story and helps them comprehend. Also your visitors are more likely to remember your site and refer it to their friends and contacts to increase your exposure.