Most images not in sitemap

Hello,

This plugin seems like a really great start. I like its simplicity and especially like the settings for choosing the sources of captions and titles.

However, our site has hundreds of images, and only 31 show up on the sitemap page. Most of the post types are selected in the settings, but the plugin does not find most of the images.

Also, our site is bilingual, and the sitemap specifies every image four times, twice in each language.

Thank you