Welcome to the forum! Where in MS are you (PM me if for some reason you don't want that public).
Whenever you upload your photos to a site, you're at the mercy of the site's parameters. Many sites restrict image file sizes and reduce them to their standards.
To avoid this, many of us post our images on other sites that don't restrict the file sizes and then link to the photo. Some of these sites charge for storing your photos, but they don't charge very much.
I use http://www.pbase.com
and pay $23 a year for 600MB of storage. If you're planning on selling your images, some of the other sites would be a better option. I think a number of the members here use smugmug.