With apologies for my tardiness in replying.....
You need to create the disc with ROM content for this to work, because to make a disc with a video playable on a set top type player it needs to be multiplexed & authored into VOB files.
Accessing single images can only be done fromn photo data so you need to author your video file to regular DVD-Video, and add your photos as a slideshow within that DVD - then also add the photos into a ROM folder, which will make them accessible on the computer.
To do this, build your DVD in the usual manner (you are using Encore, right?) and create your movie timeline & your slideshow timeline in the regular way. Once you are happy with the way this all works (and to test it, do not waste your time with previewing but instead either burn to an RW disc, or if you need to use a Dual Layer disc, compile the project to DVD folder & check in a software player.
Once this is all good, go back into Encore & add your photos again as ROM content. You will lose the slideshow functionality, but this does not really matter too much. To prepare your ROM folder, copy the images you want to use into their own folder, and name it something you will remember. Then, when you aere ready to build the disc, just add this extra folder as ROM content.
Accessing these images can even be done off a regular set top DVD player - most will support photo viewing these days (check your player manual for specifics and how to access) and better yet, most players will also play them as a kind of slideshow if needs be, or advancing manually. Best of all you can of course access the photos straight off the DVD in a computer, and you can browse them as well - they will appear under the name they have when you put them in the folder. You need to do it this way because a DVD-Video disc contains VOB files and noit separate images (even when you make a slideshow it becomes a VOB ion the DVD)
It means duplicating content - unless you are okay with the idea of not having background music or having the photos as extra content, accessible from a different set of buttons on the player - if this is okay you can leave out the slideshow in the DVD-Video, ponly adding it as ROM content - it will still be accessible from 99% of all DVD players.