@Nullable
    public View getImageViewForContentIndex(final int contentIndex) {
        final int pos = categorizedImageListHelper.getListIndexForContentIndex(contentIndex);
        if (pos == -1) {
            return null;
        }
        final ImageGalleryEntryHolder vh = (ImageGalleryEntryHolder) binding.imagegalleryList.findViewHolderForAdapterPosition(pos);
        if (vh == null || vh.imageBinding == null) {
            return null;
        }
        return vh.imageBinding.imageWrapper.getImageView();
    }
returns the image view for given image index (or null if index is invalid)
main/src/main/java/cgeo/geocaching/ui/ImageGalleryView.java