As thumbs:
<iframe id="photothumbs" name="photothumbs" height="420" width="600" frameborder="0" scrolling="auto" title="Student_and_Youth_Initiative" src="http://gallery.usgs.gov/photo_shares/thumbs/sets/Student_and_Youth_Initiative/">[This content is contained within an inline frame. You can also <a href="http://gallery.usgs.gov/photo_shares/thumbs/sets/Student_and_Youth_Initiative/">access it directly</a>.]</iframe>
As a list:
<iframe id="photolist" name="photolist" height="420" width="600" frameborder="0" scrolling="auto" title="Student_and_Youth_Initiative" src="http://gallery.usgs.gov/photo_shares/list/sets/Student_and_Youth_Initiative/">[This content is contained within an inline frame. You can also <a href="http://gallery.usgs.gov/photo_shares/list/sets/Student_and_Youth_Initiative/">access it directly</a>.]</iframe>