I don't see any IPTC TITLE, sometimes referred to as
objectName. Also, there is no "description", sometimes referred as "Caption-Abstract". You can see list of IPTC values here:
https://exiftool.org/TagNames/IPTC.html
X3 will display values title/objectName and description/caption. Your IPTC contains noen of these values. I see you have "headline" which is used by some apps, but it's not the main title.
Having said that, I think there is some misconception. When we talk about images IPTC and SEO, we are talking about search engines reading IPTC data from images, REGARDLESS of X3. In other words, as long as you have IPTC data in your images and we are talking about the concept of "improved SEO for images with IPTC", it doesn't really matter if X3 reads the data or not. That is the point of the two links I previously posted ... SEO from images that contain IPTC data, which Google will extract and read, regardless of X3.
And another thing you are over-looking, as mentioned before, adding IPTC (or not) to images, will not help Google "find" the images in the first place. It doesn't matter if the images contain IPTC or if X3 displays the IPTC (or not), if Google cannot find the images. If/when Google DOES find the images, then images IPTC might improve SEO, but this is unrelated to X3 displaying the data, although you would probably want that also.
christianch wrote:Results The exif and iptc elements are erased ....
There is nothing erased. It's just that there is no IPTC fields in your images that X3 reads and outputs on page. This does not affect images from having improved SEO once Google finds them, because Google will read the IPTC regardless of X3 displaying it or not. In fact, when X3 displays IPTC title and description, Google does not know this comes from the image IPTC.
christianch wrote:I deduce that I will therefore be required to create a sitemap dedicated to the images I want to see referenced on google.
Yes you might need an images sitemap, but not because X3 doesn't display your IPTC. Even if X3 displays your IPTC, this has nothing to do with your images getting indexed by Google or not. It's just optional on-page titles replacing the filename.