Steven, it turns out that the problem is with a particular photo. In jAlbum, the photos are displayed in the gallery grid with their file titles listed under them. For this one particular image, instead of its file title (2013-09-07-12-52-01.jpg), what is displayed is:
METADATA-START [a bunch of unprintable, unpasteable, etc., characters follow -- perhaps 5,000 in all, which mostly appear as ...UUUUU..., and concluded by:] METADATA-END
As I wasn't paying attention, and as I working with about 50 photos, and as only the start of ("METADATA-START... [some gobbledygook]") is shown in the grid with all the other photos, I didn't notice that in the gallery I created yesterday.
Working with a test gallery today, I noticed it. If that photo is left in the test gallery, and if Display Captions is set, it breaks the generation of the xml file. That file abruptly ends thusly...
<image imageURL="slides/2013-09-07-12-52-01.jpg" thumbURL="thumbs/2013-09-07-12-52-01.jpg" linkURL="hi-res/2013-09-07-12-52-01.jpg" linkTarget="_blank">
<title></title>
<caption><![CDATA[METADATA-START
...wherever that particular photo is placed in the gallery. That is, there is no...
</image>
</juiceboxgallery>
...and neither are any subsequent photos processed.
If Display Captions is unchecked, that file is processed fine, wherever it occurs among the other photos:
<image imageURL="slides/2013-09-07-12-52-01.jpg" thumbURL="thumbs/2013-09-07-12-52-01.jpg" linkURL="hi-res/2013-09-07-12-52-01.jpg" linkTarget="_blank">
<title></title>
<caption></caption>
</image>
That particular photo is one of three, among the 51 photos in that gallery, that originated from a Samsung S4 phone's camera (which I don't own or currently have access to). The other two were handled just fine; I experimenteed with a test gallery today, using all 50 photos, i.e., the same photos, including the two other Samsung pics, but minus the troublesome one.
All three of these photos are 4128x2322 to start with (my gallery reducing them to 1024x1024, Link to hi-res* via scaled images, Copy originals). The problem one is 2477KB, while the other two are 1848KB and 1602KB. Incidentally, the problem one lists normally in terms of title, 2013-09-07-12-52-01.jpg, in Windows Explorer and any of several programs with which I've opened it. I've also done a Windows (Vista Home Premium 32-bit SP2) drag-and-copy several times, and the copies exhibit the same behavior. I also saved a version of it that I personally cropped (using Faststone Image Viewer), and that, too, appears with this strange title in jAlbum.
So, what I think we have here is some odd combination of events. Perhaps something is corrupted with this one particular file, and perhaps jAlbum needs some additional defensive coding, as well. I attached the photo to a POP3 email, which I then sent to myself, via a POP3 mailer, to a gmail address, retrieved it, and saved it as a new title. That new file still presents this jAlbum problem, so I think if you (or someone at jAlbum) want to take a look at it, I think that I can preserve the problem even via email; let me know.
Cheers,
Bill