Hi there,
when the "Bildbeschreibung" text is filled with different text for different product images, VM (latest version) will
only display the text entered in the first image.
I already had kind of discussion with Milbo about this:
"Bildbeschreibung" shown is last value entered at "Bildbeschreibung" in backend for an image.
I bet you are using one image for multiple products and you have entered proper meta data for each product at this image. Last value entered is saved in db, values entered before are overwritten with it.