Hi Debbie, I have used Picasa before for mountain biking photos and have posted links onto a forum from it.
(I'm assuming you are using a Window's operating system with either Internet Explorer or Mozilla firefox)
For individual photos, right-click on the individual photo, then click on 'copy image location' and then you can paste that link in here.
For albums, just open the album up and copy the link up at the top of your browser.
Let me know how you get on with my instructions!