DLNA does not support ISO images. You will have to copy the content to one of many container formats. If the set supports DLNA, it should play them all. I can't tell you which one is "best" because opinions vary. I settled on pass through .vob as file size isn't an issue for me and I wanted the content to be exactly as it was on the DVD in terms of quality. I'd be interested in hearing what others have chosen. I know some prefer .avi, mkv, wmv, etc, for reasons of smaller file size at the expense of a slight loss of PQ.
Interestingly, my Samsung bluray player played .ISOs when I first got it. Then after an update, it wouldn't. I liked the feature because you could rip the entire DVD as a single file, including working menus and special features.