Not really, as web browsers don't support opacity settings for background images.
However, a semi-transparent background image on top of a solid colour will always look the same, so you could just edit your photo in Photoshop to do the same (put your photo as a layer on top of a layer filled with your site background colour, and reduce the opacity of your photo layer), then save that and use the modified image as your background instead.
Comments
However, a semi-transparent background image on top of a solid colour will always look the same, so you could just edit your photo in Photoshop to do the same (put your photo as a layer on top of a layer filled with your site background colour, and reduce the opacity of your photo layer), then save that and use the modified image as your background instead.
Please check out my gallery of customisations for the New SmugMug, more to come!